Wow, you guys really pay out for your exhausts!
I came to the conclusion that custom cheapie is best. My exhaust (presently) has cost me £17 ($23ish due to exchange rate) for the pipe, and some time with the exhaust off cutting and welding (borrowed a mates welder, so factor in £10.99 for the gas).
I've now bought a welder - £50, about $70, got myself a cherry bomb - £23, about $30 and I'll be fitting the bomb soon. Other mod (UK 318iS's have no cat, just 2 mix-boxes) is one mid box removed. Stock midboxes combined with backbox is definitely restrictive.