Convertible is easy to find. Esp for E36 since not may wants them.
Check autotrader, ebay and carmax. I see quite a lot of E36M3 Convertibles and early E46M3 convertibles FS these days.
PAST: 11 E70 X5M | 08 E90 M3 | 08 E92 335i | 03.5 E46 M3 | 99 E36 M3