I've been looking at this seat as well and was wondering if you've received/installed it and could offer any thoughts on fit.

I have them installed in my MSM. I ended up getting the batch of the QRT-V got them in with the RTheory seat brace and Sparco side mounts. Trans tunnel definitely needed a good banging on both sides. The seat does hit oem the door cards but eventually it molds to the shape of the seat. I have LRB panels coming to see if its better. The seats do not fit with the hard dog door bars. Ended up getting rid of them. The seats are very comfortable and very light !

Update part 2!

Turns out that Sparco had the seat holes in their QRT seats higher than their other seats, so had specific mounts made for them (go figure I found this out after installing the seat), to allow a better layback angle than you would have with the stock Sparco mounts.

In need of more layback, I bit the bullet and bought the mounts. As you see below, the standard mount (front) is about 2 inches shorter than the QRT mount (rear).
https://cimg9.ibsrv.net/gimg/www.mia...2a4aca6239.jpg

A few other differences to note: the angle of the mount is slightly different, making the seat's footprint with the mounts about .5 inch wider overall, and the mount itself is shorter in such a way that the bolt holes of the new mount don't match up to the old mount. Good news is that the layback is awesome, and the angle reminds me a little bit of sitting in an Elise seat mounted in a miata = a lot more comfortable than the standard mounts.
https://cimg8.ibsrv.net/gimg/www.mia...029a50b42f.jpg
https://cimg9.ibsrv.net/gimg/www.mia...86fee9a40f.jpg
https://cimg9.ibsrv.net/gimg/www.mia...5a8a3e91a5.jpg
https://cimg0.ibsrv.net/gimg/www.mia...23adb74990.jpg
stupid bolt holes

Bad news: As I mentioned, the new mounts sit .5 inch wider, thus making it .5 inch too wide to actually fit in the car. So what to do? Cut the old mounts that actually did fit and make them higher!
https://cimg8.ibsrv.net/gimg/www.mia...b593fbd22f.jpg
https://cimg7.ibsrv.net/gimg/www.mia...77e1c1f04d.jpg

"Custom mounts" attached to seat and seat is back in the car. I had to move seat forward a bolt hole, but the difference in seating position was more than I expected. The seat in this new position seems a lot more of how this seat was designed IMHO and a lot more comfortable to me.
https://cimg0.ibsrv.net/gimg/www.mia...4beb300c98.jpg
Seat angle makes top of seat even lower than before
https://cimg1.ibsrv.net/gimg/www.mia...d99c8bc032.jpg
Black mark on door panel was where the seat was rubbing against the door with the unmodified mounts

TLDR:
Sparco makes mounts for their QRT seats that offer a better layback and thigh support, but makes the seat footprint too wide to fit in my lowered floorpan miata. I modified the original mounts using the new mounts as a guide, and reinstalled seat to find myself not only more comfortable, but even lower than before.

Here is a great option for mounting the QRT-R in an NA chassis.

At 22" shoulder bolster width I knew this would fit in a NA, but would probably touch the door panel. I went for it and ordered one. I looked at several of the available seat mounting options and this thread trying to figure out what would work. I initially thought the Jerfspeed was going to work. After talking with Jeff it was apparent that the rear portion of his mounts were not tall enough to reach the rear mount on the seat. I don't know why Sparco decided this seat needed higher mounting points.

I don't remember how I came across it, but I found a thread on facebook where someone mentioned Bell Raceworks mounts. From the looks of them I thought they would work, but wasn't sure. I took a chance and ordered up two sets. Turns out they do fit, but only using the top slot. In the top slot the rear of the seat is about 1/4" from the floor, a bit more in the car since the front is raised up on the front seat mount beam/hump. The Bell mounts are designed to mount by removing the rear seat hump and bolting the rear directly to the floor. I had already removed the drivers side seat humps and modified my stock seat to sit lower in the car, so no problem for me.

Here is the link to Bell Raceworks and the picture of the mounts on their site. https://bellraceworks.bigcartel.com/...-seat-brackets

https://cimg0.ibsrv.net/gimg/www.mia...4c3b956c87.jpg

Mounts on the seat showing how close they are to the floor.
Attachment 228682

Installation was pretty straightforward as expected. Front two stock mounts are used. Drill holes for the rear two seat mounts and use bolts and backing plates. I did have to massage the transmission tunnel with a hammer and cut the outside edge of the seat mount so it would lay flat on the mount.

The seat sits much lower than stock and with the seat pushed as far towards the transmission tunnel as possible the shoulder bolster does touch the door panel top. The door still closed, but was touching the seat and caused some squeaking while driving. I decided to cut a notch out of the top of the panel so there would be no interference, which worked well. The seat does not touch now when closed. The next time I have my hard top off I'll get a broomstick test pic to show the height.

Seat installed.
Attachment 228683

Door Panel notch
Attachment 228684

B Pillar clearance
Attachment 228685

I am an average height around 5' 10". The seat is slid as far forward on the mounts as it will go. I can drive it great like this, but I wish there was a couple inches more of forward adjustment. I may take the second set of mounts to a fabricator and have them modified to give a couple more inches of adjustment. Or, I may just get used to it like this and leave it as is. If you are tall these mounts would be great for you! There is probably enough room behind the seat to slide the seat all the way back on the mounts. .

I really like this seat! Fits me great and looks great! I'll be getting a second one for the passenger side soon.

Reviving thread to maintain existing conversation and add to knowledge.

Considering QRT-R for my NB, I'm 5'11" (6ft if any women ask me) and 240 lbs, I think the QRT-R should fit me just fine.

Interested in using the QRT-R, would this be possible with a factory floorpan? The Bell seat brackets look like a good possibility, any idea if they'll work on the passenger side? I see they require drilling a additional holes in the rear, is that area strong enough to withstand a crash?

Yes, you can install a QRT-R on a factory floor pan. I am 5'10" and my helmet is a couple inches under my roll bar.

Yes, the Bell brackets work on the passenger side as well. I now have two QRT's in my car.

https://cimg7.ibsrv.net/gimg/www.mia...13073f4fc.jpeg

The floor pan itself is not strong enough, so you will need to use a backing plate under the rear seat mounting points. This is what I used.
https://www.pegasusautoracing.com/pr...sp?RecID=28535

I hope that helps! Let me know if you have any other questions.

Awesome, thanks! What's your waist size, how well do you fit in that seat? I'm a 38 waist so some seats are tight on me.

I am a 34. I know someone with a 36 who tried out my seats and said they were still comfortable. 38 might be a little tight, but hard to know without trying them out. There is a Sparco that fits a larger waist size, but I can't remember right off which one it is.

Yeah, I need to get out there and try something out