i have my gen3 on gas right now, i really dont think its bad in long run it will be because the engine was designed to run on petrol not gas. but from what ive been told these days with the systems they produce there isnt many problems and have been tested with lots of cars to make sure.
Gas is a much better fuel for cars in general. Gas is so much cleaner than petrol and if your car is tuned properly to use gas it will run better than petrol.
Your engine will last longer for starters and its heaps cheaper to run than petrol!
Ive seen plenty of taxis with over 1 million kms!!
All in all gas is a good fuel