The Deluxe definitely has alot more techology baked into if you are willing to part with the 6k. I had a hard on for the commander control knob for the longest time haha.
But i finally went with the standard package because the second i got into the car and test drove - all i could really care about was the way the car drove..and oh my with G vectoring (that comes standard in all 2017 m3s now) the lack of body roll and handling was amazing. I didnt feel like i was behind the wheel of a B&B car at all.
All you current M3 owners are so lucky!
On the 1.5l engine. It is responsive and has power for sure with a nice sound but compared to my previous 1.8l civic (my only recent frame of reference) it was less torquey.(obviously) That being said if you aren't looking to out run anyone on the road and just need a responsive engine that can pick up when you need to overtake the 1.5l seems to do fine.
not forgetting when you want to sell the car, deluxe actually can fetch a better price and more people are looking for too.
otherwise i don't find a standard package car any attractive apart from the $.

