alhtough this is an older thread, but if you went a head and want a full exhaust save up more money and go ahead and get your big 3. intake, programmer and exhaust. you said you ahve the K&N filter is that the drop in K&N or the actual K&N intake system? the big restriction on the 450 if the intake. The full exhaust will give you gains but the intake will give you greater gains. at your sea level a programmer is crucial if you do either or cause the stock ecu can't handle that large of a jump into a lean condition. but if you're looking for an idea. on my 450 I have 13" dasa(loud as hell not recommended for trail riding go with the 15" can), procom ecu, and FCI intake. But I'm going to change my controller to a Power Commander V with the auto-tune feature for when I change altitude we go from 5000 up to 12,000 and the auto-tune will help compensate for the changes. A regular PCIII and Procom won't adjust to altitude.