To anyone who may be wondering the DBO500 does fit perfectly well on the 500L model. I am very pleased with the results as everyone knows of the dreaded 500 bottom end. I am still running the stock tires/rims yet and i tried the recommended spacer/secondary spring combination and it helped. i could pick her up in low a little bit easier. My brother has his own 500L and it was still a pretty close race between the two, he noted he liked how mine seemed to require less throttle while climbing hills and seemed a bit more peppy in short burst through the woods. I ended up being pretty bored one day after work and was only really planning on putting the primary spring in after i had worn out the stock tires and upgraded to some taller, more aggressive ones. I swapped the spacer/stocker out for the dalton spring, buttoned her up and i was very impressed with the result it did with stock tires. I can be sitting straight up in a normal seating position and punch it in low and it will come right up on me. I can pop her up in high after with little effort. It runs on average 350-500 rpms higher than stock(in comparison to my brothers) at all times and engages at roughly 2300 rpm (vs 1700-1800). It seems to always be in its powerband now and is much snappier with hardly any delay when going to WOT. My brother is 320lbs and i am 240lbs and even if we swap machines the result is the same. Mine wins off the line, mine slowly gets away from his.Top speed was not affected which really surprised me, stock on a long run it would play around 7200rpm, now it hits 7500 and stays theres until i let off. The engine breaking is greatly improved, which i am a huge fan of ever since my first 800. Its almost in the ballpark of the 800 but doesnt have quite the hold when going down a steep one in 4wd low. Overall i paid $60 and its a completely different machine then before. I commend Dalton for a great product, and those of you who decided to read this whole long post haha.