Was informed by a reputable tuning company when I suggested a two stage Rotrex S/C may be a good idea. I presumed it was down to web thicknesses. Hope they were wrong but don't fancy blowing mine up proving them right.
We do not get the 350 this side of the pond and I think I told you the IS-F was like $104,000 here. One of the LOC UK guys has imported a TOM's S/C 350 from Japan, but I was exploring buying a slightly used IS350 engine from the US to modify and fit in my 250 shell
You'll want as much of the 350 as you can get-
the transmission is different for one (and so the ECU will likely not work with the 250 transmisson)
the 350 has VDIM, the 250 does not... so you'll need all the relevant sensors and wiring for that or the ECU will have issues as well.
Here in the US you're looking at somewhere in the 2-5k range to go from 250 to 350 (comparing new car prices) so it makes no sense to try modding a 250 much...the cheapest way to add power is just buy a 350.
You're looking closer to 15-20k to go from a 350 to an IS-F
And I'd suggest that by the time you got done basically replacing all the engine internals to lower compression, designing your own custom engine and fuel management system, and designing the forced induction system, you couldn't add over 100hp to the IS350 for less than that either.
you don't read my posts at all do you? I'm in the UK..we don't get the 350. I paid $66,000 for my 250 and an IS-F (if I wanted one) is $ $104,000 more or less. But after consideration, forget Lexus..the Nissan GT-R is on it's way and a lot more car than the IS-F for the same money.