Originally Posted by Staples

Stage 2 is going to offer the 91 size compressor housing which is pretty much the biggest unit Rotrex offers in the C38 trim. This will be for the people that want to use longtube headers or test pipes (or just want to make more power in general). The stage 1 is too small to keep up with the lessen back-pressure, so if you have anything besides high flow cats and catback, your best bet is Stage 2.