IMO Power numbers are meaningless , a car with the correct suspension setup , responsiveness , predictability is what I look for, just throwing power at a car is pointless , you need to look at it as a complete package. At BPU levels she is extremely responsive and planted , I was never in a Supra with over 430 hp mark but based on other experiences when you start getting into the higher numbers I would definitely look towards a 4WD , RWD Supra platform is getting beyond its threshold over 600 mark, driveability will be affected
BPU on public roads is very quick and will beat most cars, needs to be respected in the wet ,getting into higher numbers your reaction time/concentration needs to improve considerable , at the speeds some of the single cars can accelerate it can cause the car to get unsettled trying to get the power down , reason why I mention 4WD , it can get you out of trouble very quickly.
Ideally I would like a car to be as responsive as BPU (Sequential setup), with the possibility to crank up the power a little for the odd squirt
Munro racing Stage 4 Turbo's is what I am leaning towards for a few reasons
Price point
Can run them in sequential as Toyota intended, Billet wheels (Responsiveness)
OEM look , retain matching numbers for resale value
What really makes these stand out from the Rest is the ported housings , wastegate , eliminating any flow issues & the common issue the restricted Jspec wastegate
They are currently flowing 570 HP (at rear wheels) in Time Attack