I run the LRD pro 4 series and I love it! I have alot more power than the stock setup. my first race is next weekend so I'll see how it stands up to the others then =D, LRD sent me a Pro Flow intake and a K&N w/ outerwears, the jets they sent worked great as well!
2004 YFZ 450
LRD: Pro 4 Series Full System Chrome Exhaust,
GYT-R: Nerf bars, Chassis Skid Plate, Swingarm Skid Plate
Duncan Racing: Chrome Bumper, Brake Blockoff, Chain Guard
ITP: Holeshots
K&N: Airfilter w/ Outerwears no lid
Pro Design: Pro Flow Intake, Kill Switch
Jets: 178 main, 58 Pilot, Clip 6th postion
MSR: Low ATV handlebars
Shock Pros: Red Flame Shock Covers
AC Racing: Rear Grab Bar
2004 TRX 450R
Duncan Racing: Chrome Bumper, Brake Blockoff, Graphics kit, Seat cover, Chain Guard
MSR: Low ATV Handlebars
Shock-Pros: Red Flame Shock Covers
AC Racing: Pro Peg Nerf Bars, Rear Grab Bar