yeah, 300whp sc 4.3gear would be a blast and enough for most,

Another thing people forget when mentioning power goals, is power to weight, 200lbs weight reduction can go a long way, and also have benefits in other areas like braking and handling. As well as helping get to a level of acceleration performance that an unreliable amount of whp would need.

Cost sky rockets for same WHP if its for spirited driving, vs tracking.
and cost sky rockets from 300whp or below vs 350whp and up.

So many factors and variables to make generalized statements unless we know his specific intentions and specific budget.

didja check the TRD Giffon? ;)

stock 200 hp engine, but it laps tsukuba under a minute. that cf roof...

Yeah that’s crazy. I want to know how they got that weight down so much. Probably cost a lot, but still good illustration on what weight reduction can do for overall performance.

Our diff is Toyota/Lexus based, not Subaru. The IS250 is the exact same housing, I believe Y31, I can't recall exactly. Built FI cars are abusing them without issue.

thanks for clarifying. I had to double take. I was for sure it was a 7.5 diff simialr to the sti, s2000 and rx8

Yeah no prob. I have a spare if anyone needs one :D

not sure the difference of Y31 vs Y38. but IS250 has Y31 4.1FD, Y50 is 3.909FD. brz/86 13-16 MT / 13+ AT have Y38 4.1FD , 17+ MT has Y58 4.3 FD,
IS300 has M85 3.73FD M98 3.91FD.

All share the same carrier/pumpkin and are interchangeable. no idea if any have different torque ratings or all are the same. but i dont think people have much issues with those unless your making like 300ft lbs with a slick and launching hard.

That much gets you into a nice PTUNING turbo kit with flex fuel.

Shoot me a PM

this would also be the small supra diff? mk3 gen not the mk4

I betcha its all the same.

Yep, the R&P's that Weir Performance was making was because he also made them for the Supra.

I would start with a built short block with 10:1 (for 300whp, 12:1 is okay) compression. And, upgrade valve springs, plus an oil cooler.

Supercharger kit, high-boost pulley, port injectors, fuel pump, MAP sensor, and an E85 kit will be more than enough for 300whp.