The last time Boston United played a League One side in an FA Cup replay at York Street they came out on top (
Swindon Town in November 2005). It probably won't be quite the same this time around, but I'm still hopeful of a Boston win, so I'm going for:
Boston United 1-0 Rochdale (4250)
Updated my attendance prediction as almost 4000 tickets already sold!
Note that for games with extra time and/or penalties your prediction should be for the score at the end of normal time.