Exhaust mod question

[Bun-bun]

I'm thinking of either cutting and coring my stock exhaust, or upgrading to a set of aftermarket cans.

My question: if I do either of these, will I have to change the ECU?
Bike is an '02 620 dark ie.

[NAKID]

Coring or slip ons, no. Full system, possibly...

[macker]

I have a full system I guess, cat elim and custom tips and when I took the bike in for the 1000 km service they were surprised the bike was running as good as it was with the stock ecu, it had a little surging issue during warm up thats all.