if you can put a suntour cassette on your freehub body than you have options go to your lbs wheel in hand ask for and 8 speed cassette with the same ratios and you will be riding in 10 minutes. There are specail tools like a remover and chain whip. Odds are if you buy it at a shop they won't charge you to put it on. I wouldn't see a problem with a shimano cassette at 20-30 miles a week you should be fine at the lower end of your price list. Keep in mind when you change your cassette it is always a good idea to change your chain.