TOPIC:

I have an afterlarket 4 in 2 exhaust.

from what i have at home i can set like this:

110 main, a 20 pilot,
- needle 5DL31 on groove 3 or 4?
- i have a valve seat at 2.0 or 2.3 what is the best ?

If you are not racing 2 will do, but the 2.3 won't hurt just delivers fuel to the bowl quicker, i have 2.3 in mine, as i have removed all of the emissions clutter i am running much closer to the European settings, on your side of the pond they set them up on the lean side.