You don't need to buy the game again.... just use the disk access code ...

click the + ADD A GAME at the lower left side of the screen and add the code when Steam asks you to.

If it accepts the code, you will get the Steam version of the game free and a new access code to input when you load up the game.

The Steam version, I believe includes all the updates you want and then some. It even includes the mod 'Superstorm v3' which I helped beta test in it's day.

I wish there was a way of getting you the community made and also my personal maps made for the game. The total size of the map file even in zipped form is about 50m bytes. Sorry.

Any way, the Steam version has what you want.

Friend me if you wat to and we maybe we can work something else out.

I never knew you could actually add a prevously purchased (physical) copy of a game to Steam like that. Thanks, I'll try it out.

UPDATE: I tried, but my code wasn't accepted. I might have made a typo but I doubt it. I might give it a shot later, I'm currently busy though.
Thanks for the comment anyways!

i'm just picking up on this thread. i just received the activation code for the disc version over the phone. i entered it into steam and it wasn't accepted.

If you want this game on steam, you need a Steam Key.