O2 Housing & Manifold

I need some real advice also on upgrading my Engine. I was told to get an Evo3 Manifold. If I get that, do I also need to get a new O2 housing? I really don't know too much about this manifold and O2 housing stuff so please help me out - Thanks

Also - What kind of gain can I get from either one of those? (Hp wise).

just port your existing mani and 02 housing. when you get a bigger turbo, then step up to a EVO 02 housing.

The turbo is between the manifold and housing, so you can get either and still be OK. I wouldn't get the manifold though. If you get to the point where you need an upgraded manifold (far from stock) you'll be looking for a better one than the EVO. You can go pretty fast on a stock or ported stock 2g manifold though. o2 housing might be a better consideration, but RRE downpipes are different depending on what o2 housing, so I don't know if it would fit your downpipe.

The EVO3 O2 housing has a different abgle on the outlet to the DP. In most cases the flex section in the DP will hit the tcase. RRE changes the angle on the DP to match the EVO3 O2 so there wont be a problem. You can get tubular O2 housings for ~150 bucks, might as well go that route and save the hassle if you've already purchased the DP (for a regular O2), or just use the 2g. I used it up until my latest round of upgrades, and I'm only changing because I dont have a choice :D