03-03-2014, 08:04 PM
The actual wording i can't remember, but it's basically: If the exhaust is much different to the original, then fail or advise as appropriate. So there's huge scope for interpretation, any mot stations that actually want customers will know this and i don't think there's a large proportion that'll actually have a problem with the backbox being removed. Technically, as long as it's not excessively loud or smoky, they could argue the exhaust still performs it's function adequately regardless of how it looks.