The first thing is make sure both clutches are in perfect condition. If they are the original '07 clutches, there were several tolerance and wear issues that needed attention. A new primary Maintenance kit will address most of the primary issues that existed on the '07.
On the secondary the movable sheave bushing was prone to wear. It can be replaced. Or a Team TSS04 is a good, inexpensive replacement. I can recommend a good helix/spring combo if you do go to a Team secondary.
Stock primary clutching is decent. Secondary setup for 151-156 track I would run a 44/36 helix. Gear down a tooth at that altitude. Run the Doo -288 belt. Adjust pin weight as needed to see 8400rpm.
If its the original '07 engine, check it out closely for crank runout tolerance, compression etc....they were not known for their durability. No sense in throwing $$ at clutching if there is a power output issue.
When everything is correct, the '07 is a screamer! Probably the quickest Doo make to this day IMO.
