Should I Trade My 2017 2.0T RWD Luxury for a 2017 3.6L AWD Luxury?

Last Spring, I picked up a dealership demo 2017 ATS 8-Speed Auto with 8,000km on it at a price I've yet to see bettered to this day. Now there's an identically equipped Luxury model in the same colour, but with the 3.6L with AWD at a local BMW dealership with 18,000km on it (mine is now at nearly 21,000km). I'm not really interested in AWD, but would potentially (I've yet to drive one) prefer the 3.6L over the 2.0T (currently stock and no plans to tune it). I'm curious to hear your comments and recommendations as to whether I should consider spending an estimated $3,000-$5,000 to upgrade to the 3.6L AWD platform or stick with the 2.0T RWD.
Thoughts?