You should talk to SLP and find out what RPM the eng needs to run to make the pipe work to it's potential. They would also have their own clutching for your sled, to work with that pipe, that they have tested. I believe in 07 SLP said that pipe was a bolt on, no other fuel increase was necessary. On a 08 800 though, they supplied a resister, to plug into the pipe heat sensor wires to richen the mixture. Ask if you need that. Polaris doesn't have a "reflash" for adding an aftermarket exhaust. 4500 sounds like alot of engagement RPM. Here in the mtns in deep snow it would trench down getting started, with such a hard engagement. EPI must have given you a heavier primary spring? Lighter weights would raise the engagement more, and raise the shift rpm too. You didn't say what it runs at (shift) I think SLP wants 8200 rpm, but CALL them!
