Heya, well i have a 96 or 97 Specialized Stumpjumper, minus the problems a great bike. I want to get a new shock with more travel, i think the manitou pro x i have now (what came with the bike) is like 60mm, either way it's old and used and abused. I've heard from one bike store, that if you replace the shock the whole "balance" or something will get out of whack. Anyways could someone enlighten me and also give me a suggestion for a cheap/good shock (college student with 17 hard credits this semester). Thanks!

edit: I think if all goes well (this is my second month living in colorado, i'm REALLLLL close to moab) this summer i'd like to upgrade to disc brakes, currently i have vee brakes, should this influence my decision at all?