I'll be curious to hear how drivable it is with a 2.47. I spend hours at 80 mph at 3500 rpm with my 3.07 and 205 tires. Lower rpm would be nice, but not at the expense of insufficient power to cruise up hills at highway speed. Personally, I don't think I would try to go any higher than 2.88 unless I had some info from someone who has done it first.