Depends how long, how much, and how hard you drive it. Also good tuning extends any engines life. With MPI and MS you should be able to drive with 350 horsepower as a daily driver. You would want a non jet head and a good clutch also.
I run a marnel head with bpr8eq-14 plugs. I have had best results with them being there evan colder and have 4 grounds and a center electrode that doesnt require gapping. Its the first gen rx7 plug. Rotary engines have high turbulence and heat the first gen didnt have leading and trailing plugs and work great if the threads match. The threads match. You shouldn't have to special order, call around napas schucks baxtors and you'll find some plugs.