Hi,
I started off with a mongoose back box and centre pipe, however the backbox will need a custom bracket made for it, as the cab has a slightly different mounting system to the tintop. This was fine, and provided a nice exhaust note and a difference in performance was noticed. However because of the size of the central silencer, it did cause me some problems when I lowered the car again, so I had the centre silencer removed and a powerflow pipe put in its place. I also had the standard mongoose tailpipe replaced with a carbon fibre wrapped powerflow tail pipe. This fills the hole in the Clipper bumper nicely.
The car sounds great and goes will with it, and has a noise of 109db (meauserued) so it's not excessively loud, but will still turn heads.
Mongoose come with a lifetime garauntee, but I have probably invalidated it with the mods, but this is a good sign of their confidence in their product.
However, I would probably not go down this route if I had to do it again, I would just have powerflow custom make me an entire system.