I also have a 2002 Sport on new last year OEM suspension, bushes, arms, Showa shocks, springs with all the nuts and bolts on 16 inch wheels and found this table, https://www.miata.net/faq/wheel_weights.html which shows one can save 1.5lbs a wheel by fitting the 2005/5 type 16 inch wheels.
Then, wrap them in Nankang NS-2R semi-slicks. They may be pricier than road tyres, but you’re not going to be putting thousands of miles on them, rain or shine.