Ravenol RSP 5W-30; Texas heat, high performance engine (my twin turbo V8 BMWs that I hammered on the Autobhanen in Germany for 7+ years are all alive and well with me now, all require an HTHS >3.5- among other requirements-oil to obtain BMW LL-01, Mercedes 229.5, VW 505.0 approvals). Expensive...