i dont know much about mountain bikes(i know the basics and a little more but not much extensive information) cause im just getting into it, i have been doing bmx for years tho and want to try something new so im wondering what you people would recommend for upgrade parts on my mountain bike, its a 26 inch mongoose spark, im looking for better wheels, like double walls w/disk brake compatibility, a new crank, mine is a 3 piece with the three speeds in the front if it matters. what brakes should i get, handlebars, pedals? just looking for advice or your opinion. i appreciate the help fellow Yahoo users.