So I've searched everywhere and I know I have to be overlooking it, but where can I get a exhaust housing for my 18g? I was going to port my 14b exhaust housing to hold the 2.25" exducer from the 18g but I noticed a crack across the wastegate flapper hole so that's out of the question now. I don't need something that's super expensive but I don't want something that's going to crack or have bad flaws in it.

Classifieds or a turbo builder.

You're not going to find a housing that "doesn't crack" anywhere. Any turbine housing is going to crack given enough time. I've seen new Genuine Mitsubishi housings crack in as little as 5,000 miles...porting accelerates the cracking.

The most-durable housings made are the high-nickel Genuine Evo III turbine housings...I've never seen one of these crack in unported form. Good luck finding one, however- they haven't been in production in quite some time. So your options are a Chinese-made replacement housing at $100-$120, a Taiwan-made replacement at $200-$220, or try to hunt down a used MHI housing that isn't cracked to hell.