Well I got my 14816's installed, but it was spot on. Lou's Custom Exhaust in Worcester did the work and they were nothing short of perfectionists. I am very happy with the sound. I now routinely blip the throttle just before take off, because the Magnaflow's have a nice quick grunt when I do that.
Also, my clutch has about 6k miles on it, so I can't comment on your slippage.
Also, my clutch has about 6k miles on it, so I can't comment on your slippage.