Okay, this is the first time I've ever modified a Super Soaker to shoot Nerf darts, so I did it sort of blindly.
I started out with the Max-D 2000 gun which you can get for about $6.00 at Target. Its about the size of a Maverick, so not too bad.

I opened up the gun. There is a small plastic ring over the pump like on an AT2k that needs to be broken. Once inside the parts are pretty simple.

The first thing I noticed was that the pump was unusually small. So I happened to have a broken AT3k laying around, I took the pump out of it, cut it, and inserted the pressure tube into the pressure tube of the M-D2k.


After that I cut the white plastic piece off of the AT3k pump handle.

I then cut the O-ring piece off the M-D2k pump.

Then I hot glued the 2 inside one another which was a perfect fit.

Now this is the front cone that puts the water into a stream. VERY tiny. Cut the whole thing off.

Now attach your barrel material. I used 11 inch barrels.
It should look like this:

Now, you need to make room for that larger pump we put on, so I cut off a good section of the bottom.

Now we put the pieces back in and it should look like this:

I then took some scrap pieces of plastic I had and glued the pump to the underside of the gun.

Once everything is put together it'll shoot phenomenally! Here are my ranges:
(With out any wind, and shot in grass so there is no dart skip. All tests made with a Stefan dart.)
At 5 pumps: 98 feet

At 10 pumps: 164 feet

at 13 pumps: 198 feet

Anything after 13 pumps start going downhill in ranges.

This gun after my mod is actually quite practical seeing as you get almost 200 feet for only 13 pumps.
It's also very accurate, I can hit a moving target at over 70 feet. Next I'm going to give it an all black paint job by the end of the week.
Thoughts, concerns, praises, flames, let me know what you think!