well the big question is are you going to operate an independent boardset?
cause I think converting a Gauntlet DL boardset to Sportstation is an involved process... new video card, etc.
if you have a complete Sportstation though, one item that you will need is the I-40 interface board, it's used for the 49-way joysticks. Gauntlet for whatever reason is capable of handling the 49-way joysticks internally on its I/O.
EDIT: actually, I'm an idiot, you just do away with the couplers between the board wiring and the control panel wiring... the two halves instead of being coupled just plug into the I-40. wow I'm stupid. or I need coffee, stat. if you saw my old post, disregard the part about wiring harnesses lol