The parts you want to replace are all high $$ upgrades. You would be better suited to sell the bike off and buy a new one. The more you ride the GT, the faster the frame parts are going to wear out. GT went belly up since they built that frame in 2000, so finding replacement parts will be touggh.


For example here are some ball park figures for the parts you want to upgrade:

Rear Shock: $350
Front Fork: $350-750
Disc Brakes: $150-$500 pair
Wheels: $200-$750
Shifters: $50-$100


So even if you went super cheap on all the parts, you could still get into a nicer new bike for the same price. Suspension technology has changed alot since 2000, and you will probably find that the newer bikes ride much nicer.

Plus, it is always cheaper to buy disc brakes on a bike than it is to add them later.

Just my thoughts.
mtnbikej

 

If it rides its not dead yet so plan to wear it out before buying a new ride!

 

I had that same bike a week ago.

But I recently sold it due to a lifestyle change (read: SS bug). But good on you for riding a IMHO good suspension design that has served me well.

First of all, since you'll only be using the GT for 'transportation and occasional trail riding', you could save a bunch of money by sticking with V-brakes and current wheelset. When properly adjusted and with some good pads, v-brakes provide nearly as much power as discs. If you prefer to upgrade the Vs (Promax?), Blueskycycling.com is selling a complete set (f&r) of Avid SD7 brakes & levers for $77.

For shifters, JensonUSA sells the SRAM X3 8-spd shifters and rear derailer for $15 apiece to replace the stock Acera brake/shifters.

Next, check the online shops for a '05 Marzocchi MX Comp fork, which can be had for less than $200. 85 mm or 100 mm, the plush travel complements the frame's properties and won't affect the geometry too much.

As for rear shocks, they're a little pricey new, but if you don't mind used, you can usually find a deal on the MTBR classifieds or eBay. Remember the shock size is 6.5x1.5.

Hope this helps. Good luck.