I currently have a Petrol Ford Focus MK1 1.6 and want to play to see what i can get out of it.... Done K&N induction kit and think i should sort the exhaust out before cams, remap etc.

I can do engine stuff but never touched an exhaust...

I would like to get a 4-2-1 downpipe but i dont want to decat... what are my options?
Would i have to go with a custom exhaust? or just get a sport cat?
I would also like to keep the noise down with the exhaust to a point....?

Any help would be brilliant!!
Cheers
Jon