Iam thinking of changing my exhaust at the moment i have HKS one on with catted downpipe,Iam going to deact the car will need to have it remapped or will it be ok.I do not want to damage the engine.I have Version4 1998 STi.
Thanks in advance.

 

come on guys.

 

have a look around mate, there`s numerous threads of this subject going at the moment

 

There's no doubt that tuning them properly pays dividends. You can't do that without some kind of device to interface with your V4, either aftermarket ECU, such as Simtek or Apexi, or ESL with your original ECU.
We'd say the Simtek is superior to the Apexi, some users report good results with the ESL. All of them depend on the mapping process.

 

I have just popped a decatted on my scooby today and 3" backbox system.
Working like a treat