You know, I was just comparing the 1998 DVD to the new one and I guess the 5.1 mixes are pretty much the same. I do think that the bass is a little heavier on the newer DVD's 5.1 mix but I could be wrong. I watched the scene towards the beginning where they jump the bridge in the Bluesmobile along with the car chase through the mall scene during my comparison.
I also just watched part of the theatrical cut and the 2.0 sound is pretty weak compared to the 5.1 mix.
Speaking of the car chase through the mall scene, here is some info about the mall that they used which is still standing 26 years later:
Dixie Square Mall at DeadMalls.com
DixieSquare.com