DavidNJ

If a turbo and a CENTRIFUGAL supercharger make the same peak power at the same boost, the turbo will make more power everywhere else. Not the case for a positive displacement supercharger. None of the superchargers, centrifugal or positive displacement, can reach a high boost. But that is not the issue if you are looking for 390whph at < 10psi of boost.

Running 500+hp is virtually certain to but unmaintainable stress on the drivetrain. But if the car is running pump gas, 91-93 octane, not an issue. The turbo requires changing the exhaust, but could otherwise run the same air-to-water intercooler as the superchargers usually do. It will need some tuning to manage the boost. But that is actually a feature: boost is controlled by programming the ECU, piggyback ECU, or standalone boost controller.

Even 390whp is roughly double stock, so issue are possible. But not the same as running more.

The latest turbos, the Garrett G25s and small-frame BW EFRs, will handle 400whp at low boost. And provide good response. Kits that tuck the turbo down under the header can manage heat to keep the whole upgrade manageable. However, TTBOMK there are no kits like that with those turbos. The kits were engineered long before those turbos existed.

TriikT

I have a Ptuning AP1 rerelease kit ( GTX3076R ) Never been taken out of the box. Would knock off a couple hundred dollars if you want. Also have the walbro250 fuel pump and kit if interested.

soulicious

I’ve been SOS S/C’d and Ptuned turbo’d. Turbo is hands down better (for me), but with a solid setup and tune. I really enjoyed my time having the SOS kit. This ranged from 10psi to ~21psi on e85. It was very predictable and reliable. It’s perfect for being low maintenance. I just wanted to be able to somewhat keep up with a stock R1 in a straight line and not have to worry about belt slippage while doing some canyon carving or repetitive heavy throttle use. So turbo I went after the Ptuning kit was re-introduced.