I just got into mountain biking about a year ago. right now i have a specialized hard rock. it isnt anything special but it works for me. plus i dont have that much money to spend on a new bike. anyway ive been looking to get a 9-speed drive train instead of the 8-speed i have now but dont want to spend too much money. i have been looking at getting shimano deore cassette, chain, shifters, and deore xt derailleurs. do you think that would be a good idea? i only ride over the weekend for a few hours. also would it be better to install it myself or should i have a pro do it? any adivce would be great.