More insight from Terry@BMS:
A couple interesting charts to check out.
The first is maxed out OEM turbos compared with RBs. Both done on the same car a few months apart.
The second is RBs compared with a single turbo running higher octane and meth. It's an interesting comparison with the single as both cars are automatic so you get an apples to apples feeling for the power curves.
The single turbo clearly has the edge from 5700-6500rpm but for all around street car use does that gain make up what is lost below 4000rpm? In terms of racing I'd love to see what the 335 auto single runs 60-130. Is it going to be in the 6s or are we looking more like low 7s? Our 135 is around 140# lighter, but makes maybe an average of 35whp less from 5700rpm+ to redline, so I'm curious just how far behind it would wind up. Hopefully I can get some 60-130 testing on ours done this weekend.