I agree with Dune and ftwlth.

For starters a matching pipe and clutch kit is a must, then porting and you have to have someone that knows what they're doing to port it for you.

BTW where in MI are you located? Anywhere in/near the thumb?

I had Doug at Tri-County Equipment in Sandusky do my engine work and he did a good job for a resonable price if you don't go with RcR or Bubba to do your engine work.

try some of these mods...

2000 Scrambler 400 2x4
--Trail Mod -Ported 1k (* =included in rebuild cost along with new starter($160)and installation)
--.040 over Wiseco * $110 piston/rings $60 boring
--Head shaved .020 * $50
--V-Force Delta 2 reeds/cage * $130
--RcR HPD Ceramic Trail pipe & $230
--RcR HPD MSA silencer $130
--RcR HPD Std. Clutch kit $90
--HPD Shift Drum Conversion Kit $100 (Part # SDCK 40-36)
--Gates CVT drive belt $30
--HPD Steering Damper(7/8"stem) $130
--HPD Lower Steering PostBearing $30
--RcR HPD Tensioner $50
--K&N Filter w/O-W $40
--Carlisle Titan 489's on - (stock on machine)
--Douglas .190 Aluminum $110
--Kenda Gecko paddles on $150
--Douglas .160 Aluminum combo
--C.C. Desert grab bar $40
--C.C. Air scoops $20
--C.C. Chrome Battery cover $10
--C.C. PVT Decal $5
--P.P. Swing-Arm skid plate $55 (used)
--MSO Front Bumper $41
--Tusk T-7 Alum. Handlebars $20
--ProGrip grips $10
--PowerMadd Handguards $50
--HSP Gripper Ceet cover $20 (used)
--Polaris Gas cap fuel Gage $16
& more ???

mostly the ones near the top ; )

Jim