Actually I wouldn't, and I would not hesitate for a second to take a car equipped with the RZ on track and push it as hard as I would with any other setup we build.
The reason we have them both is because when the first NC came we didn't even bother with the soft top and went straight to the DG top and made the GT3, later when I got around to design the ND RZ I realized that some of the design trickery can be used to create an SCCA / NASA legal soft top compatible bar for the NC as well so we did.
Every design makes compromises one way or another, the RZ and GT3 just differ in the set of compromises that they make.
The NC GT3 is much wider than NC RZ at the shoulders, but here's the surprising fun fact - the RZ is slightly taller than the GT3 because the corners of the hoop are slightly closer to each other.
It's hardly any narrower than the NA / NB bars (~1" total at the top of the hoop), it's MUCH taller, and has comparable rear support to the NA / NB bars, but because of the way the chassis requires the bar to be designed it appears low.
It also has a full X brace in the main hoop which makes it stronger than NA / NB bars. Doing the same with the NA / NB bars will eat up a lot of room from the cabin, but the NC has more room behind the plastics.
True on all accounts.
Should especially note the height because the NC RZ is about a mile taller than your comparable NA / NB roll bar which make it MUCH easier for taller guys to fit.
Yes it's a different chassis but from deck height the NA / NB bars are just over 24" height while the NC RZ is over 26.5", YYYUUUGE difference.
It would appear that way because it's not as wide at the shoulder width, but the top of the hoop is only an inch narrower, so hardly any difference.
Keep in mind that unlike the NA / NB the NC chassis does have side impact beams that are connected to the RZ which makes the width of the hoop at the shoulders less critical.

Negative, the ND chassis has much tighter space constraints which the NC does not.

Excellent! Thanks for all the info.

I work 2 buildings down the street from the Haltech USA office. When I first asked about NC stuff, they knew nothing about anyone doing it in the US. There are 2 or 3 NCs in Australia with Haltechs running on a stock wiring harness, but only 1 of those was partially developed by/with Haltech. They currently have a base map for the NC but the CAN mapping is incomplete and the ABS programming still has bugs, because they haven't had an opportunity to test it and fix everything. I was going to be the first guinea pig for the US market, but I'm giving up now and going back to NB. Eventually I'm going to post on m.net for someone to take my spot and give it a shot.

The biggest downside, and the reason haltech never pursued a PNP setup any farther, is that the stock ECU connector can't be bought. The connector and pins are molded into the OEM housing and can't be removed. The only way we've found to make a true "plug and play" is to buy an ebay ECU and cut it up to create a new connector.

No problem!
I think that most people are just used to look at the NA / NB chassis which has barely a few inches worth of trim work to cover the base of the hoop and rear legs and thus leaves a lot more of the roll bar exposed, making it appear bigger.
The NC and ND have trim pieces that go up to (and for shorter folks above) the driver's shoulders, so most of the bar is getting covered and it makes it appear shorter.
It's purely the visuals, even the ND RZ is taller the NA / NB bars!

Looking into hitches now. Looks like there were some claims of the FM hitch cracking the welds around the mounting points, but doesn't seem to have surfaced much in the last few years.

Also looks like Harbor Freight has stopped selling their tiny trailer. Any other options in that size range?

EDIT: Northern Tools

Gah. Sad to hear.

jeff

Moti to the rescue. Likecat for the legitimate info. I am enjoying the ND RZ bar that you sold me!

B what suspension do you have in the garage, just so I know?

Two-way adjustable Motons with remote reservoirs revalved by HVT in Plano, Texas. 0 miles since they were rebuilt. I can't find the email with the specs on them, but HVT has a bar code on there which would make it easy for them to look it up. You know my number if you want pics ;)

It is interesting you mention shocks. Emilio mentioned he is working on providing XIDA's for NC's through Goodwin Racing. Is that still being developed?

What he said. This is the biggest frustration with this vehicle on my end. The good news was that you do not have to buy an NC ECU specifically. What Jeff found was that many Mazda vehicles of this vintage had the same ECU connector. I think the gutted ECU sitting on my desk is from a Mazda 3? Correct me if I'm wrong though.

I've had a chance to do most of the pinout on it and it won't be difficult for those of us comfortable with wiring and fabrication but for the average end user I feel it'll be a bit more work than they want to put into it. I've kinda put the project on the backburner since SEMA/PRI crept up but I'll hopefully get a chance to finish it before the end of the year and I'll make it available to anyone who wants it.

Yep. $40 shipped for a mazda3 ecu. Tons of other mazda options that use the same case and connector.

Care to elaborate on what you think an AP1 needs to be comparable to a basic NC build. I've done a basic NC build: Ohlins, flash, header back GWR exhaust, 17x9s, perm hardtop and I don't think it's that much better than a stock '03 AP1 with good tires.

Agreed. S2000 is much faster than NC for the same mods, and S2000 doesn't really NEED any mods for the track. My friend's AP2 with nothing but Ohlins and 245 RS4 ran a 1:33.2 at AMP, versus my NC2 also on 245 RS4 with a 1:38.4. He's spent a lot of time at AMP and that was my first day there, but I wasn't leaving 5 seconds on the table.

He also spent about $5k more for a clean low miles AP2 compared to my 60k mile NC2, and a replacement F22C is $3-4000 vs. <$1000 for a 2.5 MZR. I kinda think the NC is more fun and comfortable on the street, but that's pretty debatable. S2000 is definitely a better choice if it fits your budget and lap times are your biggest goal.

Main goal?

A quick car with lower cost and use in consumables than one of the V8 crushers, that will be reliable and relatively easy to work on when I do have to.

Does the S2000 have to have a hard top for a roll bar?

Neither is required. Stock roll hoops will pass with most groups. The harddog bar works with soft top or hard top though.

Pass groups or pass the broomstick?

I screwed myself up pretty good in a motorcycle wreck at Hallett back in 2007, I still have a limp more than a decade later.

Safety is something I absolutely refuse to skimp on.

Derp, I read your post wrong. I read "hardtop OR rollbar" instead of "hardtop FOR rollbar."

Harddog bar with softtop is definitely possible and preferred over stock hoops.