On my stock 2G B6, I shimmed the needles 0.5mm, drilled the pilot plugs and set the pilot jets at 2-3/4 turns out. Still stock mains.
A definite improvement in mid range and roll on performance. Well worth doing.
If your considering an aftermarket exhaust, it's almost a necessary change to put in a jet kit. Both Holeshot and Ivan's appear to have had good success with guys here.