Replacing Cat Pipe on Newage
 

So, the cat pipe on my blob has rusted and completely sheared off at one end. I would like to replace it with one of these decat pipes

http://scoobyworld.co.uk/catalog/pro...roducts_id=179

Couple of quick questions, firstly am I correct that by installing a decat pipe here, it will still leave me with 2 cats (uppipe and downpipe) so the car will still be be MOT compliant on emissions ? (04 WRX, engine wise car is standard)
Second, would the increase in exhaust noise be significant ? I currently have an non-resonated centre section and Ninja back box?

Cheers for any help

Wrong
 

Should be fine regarding passing mot.
noise level will be minimal I'd say.
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Should work fine. I'd just replace the down pipe with a 200 cell sports cat.

Cheers for the input chaps !

I have been getting all sorts of conflicting info. tbh i dont currently have the spare funds for a remap, so i was hoping that by leaving the downpipe as stock, it wouldn't require one. However dont want to run the risk of any engine damage so may set about simply finding a replacement cat.

I believe there is a lambda sensor in the cat which looks at long term fuel trim, so the car should run ok without a re-map for a while, but I wouldn't advise doing more that a hundred miles like that. It may not even throw a CEL error.