have 02 sti full decat,and tek 3 remap,need new m.o.t,changing back to catted system for mot,will this change for short time affect running or anything else when i go back to decat after mot. cheers in advance.

 

I assume you are only going to re-fit the centre cat for the MOT? In which case you may need to make sure the cat is really hot before the test.
Fit a high flow cat downpipe and you won't have to worry about all that F***ing about at MOT time!
JohnD

 

re-fit full system for mot,but will this affect remap, as remap was done around decat set-up.

 

Just for the MOT it should be fine. Drive it gently while it's on. The test only requires no-load readings at natural idle and 3000rpm It'll be quieter too! (In theory it could fail on noise level!)
JohnD