JPR

I have done a thread search but couldn't find anything on the following.......................I have a UK MY98 with PPP and want to decat the exhaust in stages, starting with the downpipe, then the centre cat, but I think I will probably keep the prodrive backbox. Can anybody advise me whether I will have to get the ECU remapped for this mod?

Could anybody offer any advice on how I can keep the noise levels down as well, I don't want be heard miles away!

ScrappyDoo2

You may be okay without a remap, but I've heard that if you don't you run the risk of overboost without the necessary increase in fuel causing a shutdown. I've got an '02 WRX which just had a full decat and Tek2 yesterday. The car is now awesome, I'd think carefully about decat without remap - speak to Merv at power engineering he really knows his stuff and can advise you. If you go full decat your car is going to be louder it's a fact you either accept or don't have the decat but trust me the performance gain (particularly from removing the downpipe cat) is awesome. Mine is straight through from the turbo (Decat up and down pipes, decat centre and magnex back box). The sound at tickover is similar to when I'd only got the backbox changed but is more rumbly when you pull off and full throttle is loud but in a grin inducing way!!

ZAZ

I ran a 95WRX with a complete HKS decatted exhaust and standard ECU for over a year with no problems other than the odd overboost in the cold damp weather so wouldn't worry too much. Most people on here either remove one or both cats but only a small amount get a remap.
Obviously a remap would make maximum use of the extra freedom the exhaust will give the engine but it's not essential!