None really, the marker rocks right out of the box. Upgrades for the marker are starting to come out.
Very User Friendly
DP Customer Service
Absolutely nothing, out of the box.. it rocks enough.
Before continuing - IMO... IMO... IMO... This gun just flat out rips! it's an insanely crazy, face mowing, monstrous, beast. Very consistent. Maintenance is a snap.. and I mean a cinch! Accuracy is on the dot, stock barrel lay's facials...IMO... Very easy to use and I mean I-D-10-T proof :). It's a high end marker in disguise.. okay well it sure performs like it but at a lower price. Like the other folks here said, "you get more bang for your buck". Dangerous Power's customer service is off the charts, they'll go out of their way to help you, I mean shoot 'em an email and they'll respond to you in less than a day and/ or maybe even in the same hour. GET THIS MARKER!! GET THIS MARKER!! GET THIS MARKER!! You won't be disappointed.
I sincerely recommend this to anyone looking for a marker that performs "high end" for the simple fact that it's inexpensive and it performs "high endly-like" :P. GET IT NOW!!!!!