Milltek Exhaust for B6 S4-to be install thi weekend at Mega4

[supraS4]

I will be having the Milltek Cat back system (resonated) installed on my car this weekend.

The closest place to me found on the Milltek web site is this place called Mega4 in Surrey, has anyone has anything done there ? Are they any good ?

Also, I have read a few posts from the forum in the US, a lot of complains about leaking exhausts, this does not seem to have an issue here in the UK. I thought the installation should be an easy job and the exhaust chould fit perfectly ? Is the leak a result of bad workmanship on the installation rather than on the parts themselves?

Should I keep the old S4 exhaust and put it back on when I sell the car or simply sell the old exhaust ? Not sure if anyone will be interested in buying, would the S4 exhaust fit on and B6 A4 ?

Thanks for any info you can share.