The Cdi is a good mod for a first timer....
After you decide what you wanna do or how you going to start upgrading there are a few things you wanna think about? First is how does it ride? I know some of use ride 0-15 mph and some ride 0-60 mph.... Lower speeds dont really require a shock upgrade cause it wont be really testing them.... The t rex shocks are a good upgrade if you want better ones as well as the sport rhino shocks... Only difference is the trex shocks will give you about an inch of lift... Which will help you with clearing slightly bigger tires... Also remeber this, you can clear up to 28's without a lift but they will rub a little in rough terrain.....
As far as comfort, a half or full windsheld will be nice. Motor cover or dust gaurd will help in quieting the motor and cutting down on the back flow of dust with the full windshield installed....
If you not a water guy, Radio, speakers and so on can be mounted anywheres but if you plan on going seat deep in water, stick it all on the roof...
Lighting, i wouldnt suggest the HID conversion... I would recommend the LED Light bars..... I find them to work much better and have a very low amp draw..... Saves on the battery and the 660 doesnt have the best charging system in the world.... lol
For the trail riding situations, the JBS sheave will help you with power, top end and lower crusing speeds for riding.... Its a perfect upgrade for anything you do with the Rhino... and can be set up to do what you wanna do with it.... Theres alot of adjustment you can do with springs and weights to make it personal....
And a 4000 pound and up winch... Dont sell yourself short.... reason being is you will pulling more people out than getting yourself out.... lol.... as they say to me when we riding... HELP....ERIC COME PULL ME OUT..... Im supprised my Viper winch is stll running
But, have fun with her and beat on the 660 hard,, Shes tough and wants to have fun... so you should to