How important is the Y pipe type?

[Midias]

^^

Greddy is a huge bottleneck on a SC car. I think it is only 2.36 inch.

[02slera]

my issue is im not supercharged yet, but hope that some day soon (in the next year) i will be, so i dont want to spend the money on a whole system thats 2.5 inch, and i dont want to loose my torque now so i dont want the 3 inch system til im supercharged. so what can i do that will make a difference now and wont need to be changed when i get the blower?

[Midias]

my issue is im not supercharged yet, but hope that some day soon (in the next year) i will be, so i dont want to spend the money on a whole system thats 2.5 inch, and i dont want to loose my torque now so i dont want the 3 inch system til im supercharged. so what can i do that will make a difference now and wont need to be changed when i get the blower?

You can pull plenty of power on a 2.5 inch system. At least 240 Whp on a 5speed is possible. Just stay away from the greddy system it is too small.

[lexmex]

Take a look at the exhaust work I've done on my RX300 (we both use the 1MZFE), http://www.cardomain.com/ride/2215309/3

I really wouldn't touch 3 inches on NA. I've got sections of 2.5 up front and 2.25 on the rear on the current (but definitely not final set up I have) and have experimented with a bunch of piping to try to get it right, but I'm sure I'll be playing around with it until the day I die.

Definitely improving the piping between the main cat and and the area where the resonator is in terms of sizing will help.

I don't have precats on mine anymore, a victim of a land called Mexico and their fine gasoline, but I'm ironically still running my original A/F sensors despite 6 years running high sulfur and god knows what it else in that gasoline back down there.