^ Wrong Mr 1.2
OE exhaust for a 172 is £350+ VAT as i had to have mine replaced not long ago. Originally they came with a standard 1 piece exhaust, but now they come in 2 sections (bb/cs).
Long and short of it is, its cheaper and a better option to take the hit and get a S/S custom made up for circa £300inc.
Other option is to goto a garage with a mechanic, not just lame fitters and speak to someone capable of mig welding. I had mine blowing like hell with a hole the size of a cherry tomato in mine. Lasted for a good few months, but then my whole exhaust dropped off in completely another part of the exhaust. Cost me £15 to have it welded up. If you go down that route, don't let anybody tell oyu it can't be welded, if they have the right skills its piss easy, as the metal is very weldable, unlike most cheap kwik-fit style pattern parts.