IMO the originals don't wear out... they just need careful, thorough cleaning.
The cheap, Chinese eBay carbs are complete unknowns and I have yet to hear of ANYONE that is very satisfied with them.
Everything is just a bit different so you have no common starting points to get there from here! Again IMO, clean and re-jet (using Dyno jets and needles) the originals when you have modified the airbox.
'01 660 Raptor, Burgard +2+1 arms, YFZ Shocks, LSR anti-vibe, CTR pipe, jetted, K&N
'01 Polaris Scrambler 400, K&N
'02 Honda 400ex, Big Gun pipe, jetted, K&N, Lonestar +2 A-arms, Lonestar anti-vibe
'04 Suzuki LTZ400
'16 RZR XP4 1000 Turbo