I've looked around on the internet, and i have noticed that the only mod's avalible for the maverick are the barrel mod & stuff that deals with "air restrictors." I decided to change that.
By doing this mod, you will increase the power & distance of each shot. The only down-side is that you have pull the slide back hard & sharp.

Step 1: Un-Screw

Just go ahead & un-screw the gun (nothing internal, though). Don't forget the screw under the slide, i always do

Step 2: What You're Doing

Pretty much, you're just adding about 1/2" of stuff between the yellow plastic & the spring. In order to do this, you'll have to cut most of the "plus" off of the female part of the air tube. Leave a little bit (about 2mm) so the spring as something to catch on to

Step 3: How Much to Add

I added about 1/2" of stuff. I used a magnet, and the end of 2 shells from the Air Blasters Double Shot. You could use pretty much anything, but i would advise against coins because they tend to be too big.
*EDIT* A lot of people are saying that they used pennies, and the they worked fine. So just whatever floats your boat, i guess.

Step 4: Experiment

Not all thing's are going to work with your gun, so experiment. In order to check if you have too much stuff in your gun, put it back together (without screws). When you pull back the slide & you don't here a "click," then you need to take something out.

Step 5: Finishing Up

After you've found the right amount of stuff to put in your gun, screw it back together. Also, don't forget this piece.
Troubleshooting: If you can't pull back the slide, then you might not have the trigger spring in place