After talking with a few people, I ended up going a different route all together since I wanted to make closer to 550whp with some headroom. I haven't got anything on the car yet but I'm going PI and also going to run the new Walbro 535 lpfp. Yes, 535, not the 525. The 535 doesn't have a check valve and thus doesn't take as much juice from the stock ekp as the 525 does. There are a few guys that run them without any issues since the BMW fuel system stays pressurized and primes before start-up anyways. I'll be FBO plus Pure Stage 2 High Flows with a custom MHD flash. I'm hoping for 550whp+ on an e85/91 tune..... time will tell.