It is rather obvious that Dinan went the piggyback route because they could not go the flash route at the time. However, flash tunes are available now and Dinan is not offering a flash tune for modern M cars such as the F85 X5M. They want to recoup the cost of investment in the Dinantronics boxes. That is fine and dandy but the performance Dinan offers for the money is considerably weaker than their piggyback and flash tuning competition.
Take a look at this F80 M3 and F82 M4 option. 20 wheel horsepower for $2500? Kind of sad especially when compared to other piggyback options available for less money.
What about a practical example on the dragstrip? This X5M with the Dinantronics Stage I tune ran at the Atco dragstrip and barely made it into the 11's after a handful of 12 second passes (car# 221):
Now look at this flash tuned example with downpipes from AutoCouture Motoring. 11.3 @ 123 in the 1/4 mile:
Eight miles per hour of trap speed on the Dinan tuned X5M? That is night and day. Do the downpipes make a difference? No doubt. Not eight miles per hour of a difference though. It is mostly the stronger tune.
What makes this especially interesting is flash tuning is cheaper than Dinan piggyback tuning. Some people even go the piggyback plus flash tune route and you can have both options working together offering superior results for less money than it costs to go to the Dinantronics route.
Dinan simply is not a high performance aftermarket option in the BMW turbo era. They are the best choice for those who still revere the Dinan name for some reason and older folks concerned about their warranty. Dinan does supplement the BMW warranty with their own warranty.
The younger BMW forum savvy crowd already moved on from Dinan a long time ago and for a good reason. They place a stronger emphasis on performance.