My better half has a '15 Mini Cooper 2-door Hardtop.
I have a '16 Mini Cooper 2-door Hardtop.
There are some significant differences--we both have the base model. Stock radio too.
Her '15 has the driver's side sun visor, secret compartment, seat tags, middle armrest.
My '16 also has the driver's side sun visor and seat tags but NO secret compartment and NO armrest. Neither of our cars have the netting in the boot.
If it weren't for my former career as a broadcaster in radio for over a decade, I might say I'm a little crazy--but I'll be doggoned if the stock radio & speakers in my '16 sound much better, more bass depth and less tinny treble than my wife's '15. And I spent a good amount of time in her '15 to be able to compare.
Neither her '15 nor my '16 have icons on the window switches.
My wife's '15--when using the FOB to unlock/lock the doors--does NOT flash the lights on the front or tail lights.
My '16 DOES flash all lights when unlocking the doors and/or the boot. I've checked the settings on our radios, there aren't any options to turn this on or off on our '15 or '16.
My '16 has heated front seats--my wife's '15 does not. I looked at both our window stickers--they're nearly the same, verbatim; except for line items for heated seats for my '16, armrest for her '15. There is no mention on either sticker about "packages" included on either car. So it seems like the manufacturer just decided to add an option here/there. We did NOT pre-order our vehicles.
These are the most differences I can think of right now, we're both on Christmas work vacations so we've spent plenty of time in each vehicle (we trade off days driving cars). Will edit this post if I discover more…though I do realize our family seems to be in the minority. Seems like nearly all the posts here are from folks with a JCW or with a lot of options…but it's fun to learn about the trade-offs/differences between what are the exact same model vehicle with the same engines & just different model years.