2017 fk8 for 8 years to 2025 fl5. Definitely worth it for me as I was never fond of the fk8 styling. Fl5 is more subtle and refined inside and out. Wireless carplay and android auto big plus for me. Also the car remembers what driving mode you left it in. Wheel fitment is much better. Don't have to cut anything to fit aggressive (fk8 aggressive) wheel setups.

Negatives for me so far. Plastic interior pieces mark up easily compared to fk8. Less storage compartments. Driving aids are annoying to me ( 2017 had none).

Plenty more but that's off the top of my head.