I own an 03 2.5 RS and wanted to buy a HKS Hi-power cat back exhaust, the owner bought it fo his sti.... will this fit my car? I plan on doing an ej20 swap this summer if that helps at all....

Being that your car is naturally aspirated and an STI is turbocharged, the exhaust components are designed differently...So I don't think it will fit.

Not only it won't fit properly, it will be too big. Not enough back pressure, you'll lose performance.

If it is true that the last cat of the sti exhaust ends in the same location and the flange is the same, then yes, it should fit just fine.

only problem is that it is probably 3" or even bigger, and there is no use for such a big exhaust on a naturally aspirated car. you would see losses in power, not gains.

If he's really serious about doing a swap, then maybe he should pick it up.

But from what I've read, these guys are right, you will lose power based on piping diameter being too big.

I wonder how that would sound? It could sound pretty mean. lol idk

I wonder if someone has a 3" catback on a stock exhaust in an n/a and has a soundclip... performance aside, I wonder... lol

you might buy it, test fit it, and if you like it, keep it on in the hopes of what comes later with the EJ20G swap. If you don't like it on there, just keep it for when you do the EJ20G swap.

also - check out reviews of that exhaust on WRX vehicles, and see how they liked them. You might find that you may not even like it for whatever reason after you get the swap completed, which would really not make any point to buying it now.

edit: that exhaust is made as an upgrade for an Sti, it is 3" internal with a 4.5" tip on the muffler... it flows real well and has very little restriction in comparison to how much the n/a motor breathes.

I would find the Carbon TI axleback and get a custom 2.25" midpipe fabricated. It would be cheaper and you won't see any loss in torque.

thanks for the help. I called Andrewtech and they said the same, thanks for all the input.