I wanted to buy a backup bike just to keep in case of an occasional friend stopping by and wanting to go for a ride, (None of my old friends ride but if they happen to stop by as I'm heading out they always like to come along.) I managed to pick up a 2004 K-2 Zed 1.0 still sealed in the factory box for $242.00 shipped to my door! After assembly the first test ride showed the rear derailer skipping second gear completely and landing squarely on third, then the shifting was pretty mundane on up through the gears however downshifting was extremly slow and hesitant from gears 8 through 5, also noticed brakes touching rim ocasionally. It was obvious a tune up was needed. A couple clicks of the mouse and I was downloading Parktool.coms instuctions for rear derailer adjustments. after following the procedure to the letter, I found that the downshifting was spot on now and there really was a second gear on the bike, however there was a hesitation on upshifting now, between 4th and 5th. A quick turn of the barrel adjuster and it's one of the smoothest eight speeds I have ridden. After trueing the rims I remembered a pair of avid single digit brakes I had taken off another bike, so I replaced the tektro brakes with them, and stopping is great. Next I replaced the multi purpose tires ( great for XC but my non riding friends aren't long distance riders so I felt a more aggressive tread would be in order ) One set of Kenda Krushers off E-bay $22.00 to my door! Now this bike wasn't intended as a primary ride or a top notch build, It's just a spare, But I'm only in it for $264.00 so even a fork upgrade would be possible and still be under $500.00, frame and fork are disc ready but wheels aren't. I wouldn't recommend this approach to newbies as the last thing you want to do with a new bike is to take a screwdriver to the derailer, and a spoke wrench to the wheels, if you aren't sure you can do the job. Also there are a lot of bikes under $500.00 in my city right now, So while my results worked great for what I needed, Your mileage may vary! I just wanted to share this story!