How easy is it to fit BTCC exhaust to standard fr back bumper?

[Moley RUFC]

Mine was about £28 I think?? when I had my exhaust done

 

[LeonFR07DSG]

Mine was about £28 I think?? when I had my exhaust done

So you bought the diffuser from seat and then it comes with a guide on it to cut out the other side? Or is it there already? Just on the inside?

 

[Moley RUFC]

I ordered a spare diffuser in case they trashed the original one which they didn't. There are markings on the diffuser so would be fairly easy to cut.