Is there an actual advantage to BBP vs SBP?

Race cars dont have spare tires lol

I think it would be wise to do the axle conversion if that will wirk with your wheel setup, however certain applications leaving the rear sbp actually helps with wheel and or tire choice. For example my front is lbp and rear is sbp. With one inch spacers on the rear the lbp 15x7 rallye wheels fit perfect with a 275 tire. I think it would be dependant on wheel tire setup as to which way would be best