Currently my engine is removed due to a faulty Ko4 and i am almost ready to put it back with rebuilt K04s. I realize that after all this work i am not going to have any real benefit other than a running car. Currently my exhaust set up is piggie downpipes with an APR stealth catback. I would like to remove my main cats and run straight pipes.

How much HP should i expect?

Should i weld them in or not? If not what should i do?

I believe the stock exhaust pipe size is 2.25 in but im not sure. Could someone clarify this for me?

Thanks
Evan

P.S I’m looking for RS4 intercoolers also. Cash in hand. ;)