Is it normal for the z which has been de-catted to smell very slightly rich and have a very very little amount of black soot visible on the bumper, the rear box's are nearly flush with the rear bumper mind you.

Im not sure as im new here but noticed mines a little rich untill warmed up,party cold running settings and the set up i have i would imagine.

I am far from an expert, however i believe a petrol smell can be the fuel pipes under the bonnet, easily cured by a Braided Fuel Line from Smithy's. I apologise if that does not answer your question even slightly. :wack: At least i'm trying :)

There is no reason for a de-catted Z to run richer than normal, but it is quite common for all the turbo cars to have a slightly sooty exhaust.

Cheers, will have to get some. Do you lot get a bit of black soot on the rear bumper?

No soot on bumper,my pipes about 2" proud but slighty sooty end pipes as Andy said.