So sorry, but many Firestone's = Junk , a High End mechanic ( Jag,Rolls,Mercedes, Ferarri,Lotus) once told me "don't buy ANY Firestone / Bridgestone" - If there ARE good Bridgestones ( they DO exist) Waaay too expensive for what they're worth.
Prior to this tip , I had only one set of Firestone (Indy ??) 500's on J30 around 2001 ?? They were pretty smooth 80 mph V-rated ride quiet , 2ply sidewall / 5or6 ply tread(tough enough) but the J loses it's AZZ and those 500's could'nt hold the back-end coming loose very well - few tires on a well tuned J30 can hold the back-end though. Gotta be super wide to do that .
Continental gotta have THE best in all facets ,after that = upper eschelon Ventus ,Michelin ( if ya can stand the price-still great tires) ,the better Goodyears, after those " never know what ya gonna get" performance wise