Got the kit fitted earlier today, just need to get a badge to put on top of the engine cover and am also going to get the shiny heat shield as the current was has rusted away at the bottom and come loose slightly.
Everything was really easy to fit, in total in only took about 45 minutes and must of that time was trying to find a dropped nut on the under tray of the car.
Took it for a quick spin and you can hear a subtle suction noise and the dump valve is not too loud thank goodness, I don't know if it is because the Monza exhaust drowns out the noise, you can hear it with the bonnet open however I couldn't hear it when driving the car.
In terms of performance I am very pleased, the car feels smoother, not sure I notice much of a difference in terms of speed but definitely smoother and not getting any flat spots that I was having with the TMC box before.