I have the same bike. I'd dump the porky HG 50 cassette first if I we're you. I orginally was going to change the shifters to XT, like I have on another bike but never did. The bike shifts well enough for me, especially since I put a Sram 990 cassette. So far: new wheels, tires, pedals, handle bars, stem, grips, seatpost, chain, cassette, to get it the way I like it. But I like swapping parts. To go Sram shifters you would need to go sram rear der. Great bike though, huh?