I have flowmaster on my truck, Super44's to be exact and they sound awesome. Now that sound on a foci though, no, don't think you'd get the same reaction. I had Magnaflow on my last foci and have considered it for the SVT as well, but I'm thinking flowmaster would be too much. Better for larger vehicles. If you are hell bent on the name though, the Super44's are very small and have just as much gain and sound as the Super40's.
As for this, I'm hoping you are just talking about for the foci, because flowmaster is a tried and proven system on muscle cars and on trucks! IMO, I see this as the same ole' debate of ferd vs chebby, flowmaster vs magnaflow, etc.