modification is good (except portwork, you want to do that to your style), if its pipes that you dont desire, you can at least sell them instead of stock. Anything that isnt stock is worth money.
Just to give you an example. I got a really good deal on this, but I got a 2001, guy hit a stump and put a hole in the bottom case and clutch cover of the engine. It had pipes, aftermarket air filter setup, durablue axle, rims, tires, front bumber, things powdercoated, and overall a decent bike.
I paid 1300 for it, through my spare engine that has a cool head, freshly rebuilt, and needed a clutch for 1000.
I now have 2300 into it including having a spare engine basically which I can part out for at least 600.
like I said, I got a good deal, but this was in NJ and and it should kind of put you in the ball park. I see quads go for cheaper around here than the 3000 at most he should get for that quad. This quad out in California might go for another 500-1000.