Am I crazy, or is this reasonable?
 

TLDR: I want a Miata, but I need one that makes boosted power. How reliable is a boosted Miata? My target would be 240-280whp on e85, and from what I've read, the NC is the best platform for boosting. Assuming professional tuning and installation, can I expect the car to spend more time running than on a a lift?

I have a 75k mile 135i, n55 running ethanol with a hybrid pure turbo , fbo, sts XT coilovers, and a few other mods. I love the car, one of the last hydraulic racks bmw ever made.
But it's super unreliable. Nothing catastrophic, just tons of little issues that shut the car down repeatedly (water pump, starter, tstat, hpfp, faulty ekp, all the fun stuff). It goes in to get the EKP fixed tuesday, so she'll be healthy again an likely for sale.
I work remote, all my driving is for pleasure (I daily a CX-9 for kids errands). I'm 40, been doing the modded import thing forever.
I'm a huge Mazda fan (and corp employee). I had an NA in high school (and an SA RX7, and a first gen Mazdaspeed 3) and have always wanted back into a miata. With my bmw constantly needing to go to the shop, I am hoping for a more reliable canyon car. I live 2 miles from Angeles Crest, so I'm up there very often with some friends (gts 4.0, m8 comp, and a zr1 round out the crew).

I'd like to make about 300hp at the crank (eventually this probably grows into a v8 or built engine miata). From my reading, the NC seems best capable of handling this type of power. I don't want to do an engine build or transmission build yet, I want to buy a plug and play kit that can be installed by a pro over a weekend. My budget, with car, will be somewhere around $20,000 (or whatever the bmw sells for). Part of me thinks it's most logical to buy a salvaged miata and just do a basic chevy v8 swap, but that will take forever.

I've got probably 30 trackdays and 5 years of beating on mine (25k miles?). "rods-only" bottom end build, oldskool gt2860rs, ms3x, e85. Makes 310whp on "allofit" or 265 on wastegate (mostly what I use at the track).

I find the actual turbo/engine part of it to be extremely reliable, it's all the little stuff that you have to tinker with to make it work right. Some examples:

- Ducting, ducting ducting. Finally got my ducting/cooling setup dialed in and no overheating. Even with a big rad and reroute, without good ducting your shit will overheat.
- Catch can filling up issues at the track. This was due to how I vented the PCV side and the track having a lot of left handers (pushing oil towards the right). Capped the PCV side, bored out the exhaust side (KEPT the baffles), and ran 2 large 10AN lines. Went from filling up the catch can in a single session to never having to empty it all year.
- Spark blow out. I had ALREADY upgraded to COPS to solve this, but it kept happening at the track. It was the heat I'm guessing. LSX coils fixed this one.
- Power steering blowing out of the reservoir. IDK if I had a bad pump, or what, but this was a struggle. Went to proper de-powered rack.

Lots of little shit, and tons of chassis tweaking to finally make the car work (at the track) with the power level it's at. I wouldn't hesitate to boost the shit out of a BP, and if you don't plan on tracking the car it will be that much easier. Just make sure your tune is dialed right off the bat.

That said, now that the car is dialed it would definitely hang with the cars in your crew. I usually am able to take out z06's, porsches, cobras, and the likes at the track. The car is an animal at 250WHP, let alone 300+, so you are in for a real treat.