if you have 1 broken motor mount the other is likely worn and the tranny mount as well. spend the money now and replace all 3. if not you will be paying labor all over again to do this repair down the road. just my .02
with over 2 million miles driving everything from a 7 speed to a 21 speed triple stick mack i know a bit about shifting. the closeness of the gear is what allows you to start in the higher gears without slipping the clutch
with the xfire 6 speed it wouldnt be advisable to start in 2nd on a regular basis. use 1 to get rolling then shift. again my .02