Thanks for the responses, I have had both companies email me with good info. ETM said he would use a GT42 for a jig he doesn't have a BW s300sx 83-75 so he couldn't guarantee fit up, which I do understand.
Here are some pics of the BW and others
turbos from L to R -- TSGT40R, GT37R, BW S300SX 83-75, TS35R, BW S200SX 75-70, TS3076R
What are some thoughts about the turbo size and using a GT42 as a jug? I don't want to buy a manifold and have it hit the strut tower so I'm trying to get as many opions as possible.