The ball joints are pressed in and the replacements i think they are not grease able anymore.

I started out with installing the Belt of the sportsman quad, It will shift hard at first and about 10 miles of hard running it will loosen up, I installed the SP ECU from the same quad and that moves the rev limiter up and give a better fuel curve for the engine, I have heard that some of the after market re flashed ECU don't work well on stock cam engines so be careful on those, the belt and ECU should get about 3 more mph out of the machine to start with, Also install a clutch kit from Dirty dog performance or speedworxs or even EPI and that will help also.

Did you mean the FS DIGITAL IGNITION CONTROLER or the FI CONTROLER, as fare as i now the ignition controller is not out yet and i just checked there site, If it is the injection controller I would have used the one from boonedocker or the one from power commander, You may want to check the PRC site because they have a lot of people that have settings posted, I am not sure for the dynatech though but they may have setting there, It is just not the box of choice on that site and they have a lot of top people there that can give you advise and know what there doing.

I am not sure if you did this or not but If you change the pipe you will need to add a injector module to get the most out of the pipe, They re map the fuel curves of the fuel injection so you can rich en or lean out the fuel map from what was changed when the pipe was installed, Then you will see more power, Some of the brands out there are power commander, dobeck, and boonedocker, The boonedocker seems to be the easiest to set up, When you put a pipe on a bike you normally need to do a re jet and this would need to be done as well with the fuel injection or you will run lean, the stock ECU was tuned to run on the stock pipe and has no o2 sensor to make the adjustments from the change of pipe, it is not smart enuff to do this.

I know they have not changed the standard RZR but they did add a new one to the line up, I think it is called the RZR extreme and it has factory long travel kit and a HO 800 motor and runs 65 mph and may have a face lift too. 

I use synthetic 90w gear oil and the level is no less then 3/4 in below the hole. I run mine at level with the hole, Polaris specs there own fluid and gives no info on it if you want to use there stuff it is called Premium ATV Angle Drive Fluid.

I would pull the fuel pump out of the tank and make sure it was not damaged during the roll over, Sounds like the pick up on the pump may be damaged. also how old is the fuel filter and how many hours on the ranger. You may want to put a fuel pressure tester on the injector test port and recreate the problem and check the pressure before pulling the pump and see if the presure changes.