If you do go with '07 or later, follow buddybr's advice. You need to "lever alone" because the Chinese pressed cranks and the increased factory spec for crank runout won't tolerate much upgrading. Oh yeah, forgot to mention the new temperature guage that now goes to 300*; an upgrade from the 250* guage; gotta love that. :s
Seriously, the six gallon tank is a nice feature. The six speed is a matter of personal choice but unless you roll up a lot of touring miles, you won't spend much time in 6th gear. As for the bigger engine, an earlier 88" upgraded to mild 95" will run with the new 96" and, in most cases, will run stronger and cooler.:yes
There are some killer deals on the earlier models because so many agree with buddybr and are upgrading to the later models. :cheers