I am going to be getting started on my DYI Projector soon. The kit no longer contains the ballast. When I go to local stores are there any specific requirements for a ballast or just 120/400w? Just 1 pair of out wires? Also apparently this one store was talking to me about some sort of newer electronic ballast? Anyone have a clue what he might be talking about and if it would work?

You would want to get an electronic 400W ballast. They are more expensive than a magnetic ballast, but they are far superior. (lighter, cooler, better lamp life, easier to work with etc..)

The type of ballast must mach the lamp so you will have to tell us what type of lamp first.

The e-ballast is lighter but more prone to failure than a coil ballast. I don't think they run the lamps any better either. unless you are taking your PJ to a lan party the extra weight should not be a problem either.

Thw SD400 lamp needs a S51 ballast.

I've got a Blueline 400w eballast and it runs my bulb WAY better than my Advance magnetic core ballast. The bulb runs brighter, more stably(no flicker), and the ballast is WAY cooler. The bulb comes up to full power faster and the blackening(a product of coil and core hard starting on the electrodes causing migration) that was happening in the ark chamber with the magnetic has ceased now(this means the lamp will maintain a higher lumen output longer as well as reducing color shift).