This is only a MK3 with a 1JZnotathe lattermodle with the2JZ. It would be hard for this car to make 400 HP with out spending some time and money and would reqire more than just turning up the boost. Upgraded turbo, Full exhaust, FMIC, Fuel managment, injecters, cams,and a lot of boost might get you up near that mark but it would be a push.
The R32s turbo isnt much bigger if anythan the stock supra. And for being the only inport to hang with muscle what about the EVO, STI,both low 13 carsand what about the 3rd genRX7.

 

LOL i know this thats why i said JK. The supra is a great car.twin turbo24 valve twin cam inline six. Whats not to love. The car can gain power easy and is a blast to drive. Its a little on the heavy side but it more than makes up for it. Even the single turbo like the one we are talking about somting like 235BHP.

 

I used to have both the MK3 87 supra and a 94 twin turbo supra, both were stolen [:@]
If there is one japanese car i would buy again its a 93+ supra for sure. I made well over 775 whp with very little upgrades. Here is the link for some major power that the camaro world would even drool over.
http://www.suprastore.com/45suppac.html

 

forgot bout RX7, and i hate EVOs lol.

 

and STI's are wicked too. but even though there stock, they come stock with most of the tuning stuff already done.

 

I dont think changing out to a single turbo, injecters, a full ECU, full Exhaust, FMIC, Fuel rails, and cams are just a little. And thats only to support up to 750 HP not to produce it. The kit makes a 570 HPon pump gas. For that price i can build one hell of a LS series engine.