Mules were designed for an entirely different purpose and were set up for stump pulling and towing on job sites and farms. They do not have the gearing to go fast and were conceived before the sport utility idea came around. Now days there is two different categories in the UTV world and the first one is the work UTV class and the second one is the sport UTV. Mules and the ranger 500 and the Honda big reds as well as ranger xps to a point fit the work category class. Even the rhino was meant at one time to be in this category and still is in stock form but with modifications it also fits the sport category class as well as the Ranger Xps. The Ranger Xp is kind of in the middle on the two categorys. Teryxs and RzRs were always meant to be in the sports UTV class as well as the arctic cat line. Others that are strictly in the work classes are the John Deer gators and the kubotas as well as believe it or not the Husqvarna Utv line as well .

There is not enough info to pin it down on what you are saying but Polaris xp throttle cables after they get a few years on them tend to become a little sticky and erratic with the throttle body just like mine did. I used liquid wrench and air to clean out the cables and then forced royal purples max film lube into them to lube them. The other main thing that happens is the drive belt wares out and they really get jumpy and erratic when you press the throttle down to start moving. As for the spring it will only make it worse because all it does is raise the stall speed or engagement rpm of the primary drive clutch and it will only add to the problem. If the pedal feels good then the problem is the belt and i would check the drive clutch to make sure it is working correctly.

Polaris rangers built from 2007 till now have the digital gage read out and 2006 back will have a check engine light. The light will not go out till the problem is fixed or the bulb burns out. If you have turned the key on and off a full cycle then there is a problem that needs to be corrected. You can remove the negative battery cable for a few minutes to reset the ECU but if the light returns after the reset then you will need to ask the ECU what the code is and correct the problem or problems.......

It is made by a company that has worked on Polaris machines longer then most people have and they are very well known for a good product. they are very knowledgeable on Polaris snow mobiles and ATV/UTVs unlike some of the companies out there that just jumped on the band wagon and adapted something they made for another manufacture without even knowing the ins and outs of the machine they are modifying for. They are one of my top 5 companies i would recommend on any Polaris build up......

www.hotseatperformance.com

Anytime you change the way the engine brings air in and out of an engine there needs to be changes done to the air fuel ratio. Polaris ecu's do not have the ability to see how the engine is fueling and make its own adjustment because that would require an o2 sensor interface from the exhaust and the ecu. Temperature and altitude will decide the difference if you will run to lean or way to lean when you improve the air flow of the engine. that is why you either need to reprogram the ecu or install a fuel control module with an air fuel gage to see how the engine is burning fuel. Since you are at 700ft I would not do the modification without the controler.

Remember that Polaris rangers use like 3 different bulbs from year to year. I think 2005 and 2006 have the same bulbs and 2007 and 2008 have a different socket and 2009 and 2010 again use another type of bulb. As fare as the last time i checked that there is no direct replacement HID kit for the 2005 and 2006 models and require you to Micky mouse the housings to make a kit work. That is why i never used the HID kit on the 2005 for this reason and i noticed that on your site that it is not year specific for your HID kit  :?: .

http://1offmotorsports.com/p-1462-offroad.html

The name is dirtydawg not dirtydawn but come to find out that his web site is down and i am not sure when it will be back up. I will keep you posted on what is happening with it when i find out.....