I don't have a BDR but I do have a 3.46 differential, the .82 TKO 600 and the Roush 402R.
I am in Kentucky. Most always back roads and seldom Interstates.
I would pair the .82 with the taller 3.46. All the gears are usable below 70MPH whereas I would find the motor lugging at 70 with the .64. The 402 would like to be at 1800 rpm or more. I have no experience with the shorter differential, but I would suggest you calculate first and second gear speed ranges with that combination. I suppose it would chug around the parking lot better though.
http://www.secondstrike.com/Technical/GearCalc.asp
I you planned to do a lot of cross country (1000+ mile) drives, I might be persuaded to recant my position.
The TKO 600 is rated as being stronger. Mine has been perfect, but there have been lengthy discussions about durability with slicks and heavier cars.
Ciao,
Chilibit