dunno,
so you will pay 4-5K$ just for the 0.5L increase... The 0.5 will get you less lag by 400-500 rpm at best...Full race mani + back door fmic etc etc you will get what 900rpm less lag at best...keep in mind that you will pay AT LEAST 3-5K$ for the mani and other stuff,
If you ask me...either go KA rebuild and turbo it...BRAD D on KA-t.org made 630WHP threw C4 AUTO trany on his S14, Some random dude made 655whp threw Z32 trans...
OR
Swap a 2JZ-GTE granted you will pay lots and lots of $$$ to do it...but the 2JZ-GTE is bullet proof and will make 700-800 WHP on S T O C K internals....and it's a 3.0L engine and can be stroked to 3.4L (will cost you around 8K for the stroker kit and you can made up to 1400whp with it)
YouTube - Cody Phillips 1399rwhp 6 speed Supra
Your call