Opinions of engine build up

[JET]

I wouldn't do BB for a 50 trim, it spools plenty fast like it is. The difference is probably small. I had my 5 knob SAFC if part of the 50 trim's life, then went to the AEM. You would be fine with a newer style SAFC. If you do a SAFC, you want injectors sized correctly. I used 660's with mine, you could maybe go up to 750's, but that would be it unless you want to do E85.

I would go external gate, you would want to do that off the O2 housing, not the manifold. Take the money saved from not going BB on the turbo and get a nice O2 housing with external gate. 38mm should be plenty.

My 50 trim lasted me quite a while and went to a new home, then about 3 more the last I knew. My SCM61 has been great also. If you have any more questions, feel free to ask.