Todd,
With the power you are running those 28 spline axles are the weak point and if they "go" it's gonna tear things up. Then you can add a towing charge on top of everything else.
If you can afford the swap then for sure you should do it. The street performance will sure be more enjoyabe. I didn't have a locker in my car before, but the posi was pretty worn and the left axle had a twist in the spline. I switched from 3.23 gears to 3.70. It made all the difference and only upped my 70 mph rpm by 350. 'Course you're running a lot more power than me, so your gearing is probably just fine at 3.20. My $.02 worth.
Bish