Hi There,

Okay first things first. An exhaust usually comes in 3 sections. front, middle and rear. From what you describe you may have had the rear section replaced (tail pipes) because of corrossion. It maybe that either the middle or rear sections have now corroded also and you have a hole in the exhaust system causing the tractor like noises. Your best bet is to get it to a daihatsu dealership/service centre for them to take a look and get the offending section replaced.
Not to worry you but the exhaust system on the YRV turbo is custom made by Daihatsu for the U.K market and is known to give problems. Your other option, although I don't think you want to go this route is either buy a complete new stainless steel system like a blitz nur-spec R (Something I have had fitted recently) but is a loud boy racers exhaust, but is guaranteed for a lifetime. Or as some has done go for a custom mdae stainless steel exhaust system but you need to look around for these type of places.
Either way once that offending section of the exhaust with the hole has been replaced the next section of the exhaust will be next likely to go and need replacing.

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'53' Plate Yellow YRV Turbo/ '53' Plate Black Subaru Impreza WRX STi PPP
130BHP/305BHP