Ok I know that since I'm going with MS I have to ditch my 4:1 FMU for Aeromotive 1:1 FPR. I'm a bit confused here tho. It looks like both of these units install exactly the same. What bothers me is my Holley 4:1 is an FMU and Aeromotive is FPR so at this point I thought I understood the difference between the two but apparently I dont. My understanding was that FMU raises fuel pressure for boost (which seems to be the case with the aeromotive as well) and the FPR maintains pressure between the rail.

One more thing.... it's taken me a year to figure out that my FMU has failed and caused my car to lean out when it goes into boost. For the longest time my only fuel system mods after turbo was a 255lph Walbro fuel pump and the Holley 4:1 FMU. Any ideas on what could have caused the FMU to malfunction and stop working? Just a bad part?