I'm 160lbs, bike is 42lbs, I have a 450lbs spring on my Fox DHX 4.0. I've always wanted to do Whistler and a buddy suggested I get a firm spring for my fork and a 500 or 550lbs spring for my Fox 4.0, but I can't find any 550's on Ebay. Is there a 550? Would 600 be too much? I'd like to have a plush ride but I hate sag so I twist my spring up and it gives me the ride I want but I'm afraid if I go to Whistler in the summer it might not be what I need. And will I see that much difference in just a 500 from a 450?