They are a vendor, oddly enough they changed their official name slightly since my dealins with them. Anyway i have their head. Had to send it in 3 times total. Had a shop vac test it locally and they said it was good.
My back was really injured last year and i got out of everything. It really broke my god damn will power! The constant disappointment was overwhelming and i just said F it.

I just torqued the head down a few days ago. Going to do timing belt and bolt on accessories tonight. I'm just crossing my fingers. I have a tremendous amount of money into this current build. I'm going to trust the machinist who vac'd it last year. 3rd time was a charm? I hope. It's going to actually be ran in 3 to 4 weeks.

Go to JAM or message Bogus. One and done. SIM isn't a BAD business they just have/had a shitty machinist. The 4g63 just makes otherwise good machinists look like idiots. I've seen it first hand locally and documented it on the site at some time.

SIM has a new machinist/engine guy who is very well experienced and has built thousands of 4G63/4G64s. I'd personally give them another shot in the future. He just started a week or so ago.