ok... someone once told me (not here, you guys are smarter about cars) that by putting my magnaflow hfc headers and bigger piping he said the HFC would be clogged in a year or two and need replacing.

My car sounds fine. With the new MN winters.... I was under there the other day and that HFC has got a smootch coat of rust under there. it's not got any holes or anything like that.

heres my real question: ready?

Lets say, for any reason, I did need to replace that HFC... I know the shops cannot legally touch any smog device unless its defective..... so can they touch a defective, HFC? and replace with HFC? I found a good muffler shop here - he's real reasonable and a good buy but the only reason he helped me last time was all the work was right AFTER the hfc - the headers were already on too.