Yeah parts are probably going to be expensive, but did you read this?
"As part of Polaris’ strategic alliance with KTM, the Outlaw 525 has a powerful 510cc KTM engine, is leaner at 395 lbs. and is the fastest accelerating production ATV available. "
Now thats probably with a restrictive exhaust, I dont know if this is true or not and nor do I know what you have done with 450 but this thing must rip, But on the motocross track
, yeah right. Maybe the engine would be good, but the IRS, from what ive heard doesnt do well at all.