take out engine. but inside boot of rocket powered car.
only way your gettin a manual unopened 25 to do tens in a rwd 33.
ooooooh buy gts4 drive train...
this is pretty much what i was going to say.
but its a circuit only car. set it up for drags. strip weld, lighten, full slicks, dif, suspension.
it will cost a f**k load to 10sec a 33gtst.
tell him to buy am rx7
give alist of specific parts mate.
no doubt it will end up in western subs being stripped for parts. keep an eye on gumtree and drift sales page on face book.
dont worry about restricting the radiator.... you have no where near enough power to do that.
my theory is after a few laps of full throttle you ic is getting warm. maybe try a front mount.
depending on the coils he put in they could also be breaking down due to heat.... remove cover if you can to increase air flow.
also if you have apod filter put standard air box back in. same thing happens as with small ic, filter starts sucking in hot air from engine bay and you lose power.
right an update..... i have my hsv so i really have no need for the 33 anymore.... will take offers around 6-7 maybe less. have just baought all adjustable camber toe arms for the rear and a diff alignment kit (pineapples) not fitted but will come with the car.
come drive it youll love it guys. reg till nov and can send you to a guy for rwc. no issues.