made the same swap back in '07, going from a 6AL which was trouble free for thousands of pass, to a Digital 6 Plus which wouldn't rev pass 3100 RPM without banging and backfiring.
Pulled only the box out and reinstalled the 6AL and all was normal.
After trying 2 more Digital 6 boxes and changing every part of the ignition system except one, I finally found the culprit...the magnetic pickup in the MSD billet distributor which not only wasn't an issue with the 6AL box, it was also less than 2 years old.
Swap it out, reinstalling the 14 year old pickup it replaced and never had a problem again and it's still in service today.
BTW, the only step up with this box over the 6AL is the retard functions. There is no on track performance gain to be had. It wasn't worth .01 in my car.
