I cant remember the exact dimensions, I was reading up about it while ago, but when boosting you want to aim for less restrictive volume and the GEMS mani can be enlarged further easily where as the banana THOR cannot, plus its not an ideal design for bolting a SC to.
Dry sumps don't look that complicated, I saw a build on one a few years back and it didn't look complicated then. I'm tempted to have a bash at making one myself as the RV8 pumps are something to be desired.
May I ask why you want to aim for such a high PSI?
Check these guys out, they import yank motors for similar money your looking at for a boost kit if you do decide to go to the dark side.
https://www.facebook.com/DLAxles?fref=ts