Hi All,Whats the way to replace exhaust tips that have gone past the point of recovery? Wifes S3 tips are rotten and I cant be doing with the hours of effort of trying to bring them back... when I know they're beyond reprive!Can new be bought from the dealers? Do they pop rivet on (like my M3) or are they part of the backbox and will require cutting and welding?Anyone replaced theirs? Advice and opinions welcome