Just finished reading this thread while in the dealer getting a new active DEF tank and contemplating buying an X5m or upcoming Raptor.
I love my x5d and the fact it's paid for.
Contemplating getting a tune and downpipe but if i can't pass TX emissions then i'm stuck.

I pull a Spec E46 race car with a fully stock x5d and it works great. More power would be even better.