D8 = Polaris Dragon 800 (IQ Chassis)
Pro Rear Skid = A new Polaris Pro Chassis rear end components
I bought an 08 Polaris 700 before last season as my fist sled. I haven't had any problems (knock on wood) other than normal maintenance. I replaced the front end plastics and bumper with a 2010 IQ front end kit from Polaris ($500). I highly recommend upgrading any IQ to the 09 - 10 front end as the 08's and older had cheap plastic front bumpers and were "bulky" with all the extra plastic. For your first season you'll need a strong front bumper as people will be pulling you out of trenches all day ;-). I bought my 700 with ~500 miles on it. I also replaced the exhaust valve gaskets, replaced the exhaust manifold gaskets, put in new plugs, changed the chaincase fluid, lubed the chassis and driveshaft, cut the windshield, took it to a mechanic afterwards for a sanity check, and now it has ~1200 miles on it. I felt some "bogging" on my last two rides, so I'll be cleaning the power valves in November.
Now that I'm heading into my second season, I can definitely see the benefit of some extra power in deep technical sidehilling and tree riding, but most of my faults each ride were due to rider error, not lack of power on the sled.
Just my $.02.