The last time I looked, Enkei RPF1 was the only lightweight choice. A quick search found these https://www.amazon.com/Enkei-RPF1-Silve ... 661&sr=8-2
. I understand 45 mm offset is better, however you should be able to make 38 mm work.
2010 Grey MX-5 GT, 6-speed Manual, Sport Package, Roadstersport Street Single w/Baffle, FCM Coilovers - "GT" setup with KBO & Ripple Reducer, Enkei 17x7.5 wheels, Goodwin Underbody Braces, Cravenspeed Shift Knob