Having analysis paralysis and the GC 0w-30 finally got to our Autozones and I have a friendly manager deal if I buy at least 12. Would GC be a thick enough 30 in constant 90-100F heat days? Rarely below 32F in "winter" here! This rebiult engine ran Castrol GTX 20w-50 the last 12,000 miles after a 10w-30 break in. A bit thick and Mobil 1 5w-30 now made me think a 20w-50 might NOT be "best". Owners Manual says 5w-30, 10w-30 and 10w-40. If the MAIN and ONLY ADVANTAGE of Synthetics is longer OCI, then these are not for me. Marginal advantages then cost/waste is not important. 6 miles to work but only 180 days a year. Some desert/mountain 4x4-ing, no heavy loads or hard driving, rarely WOT, oil gets warmed up good on the highway at least every weekend. GC 0w-30. Mobil 1 TSUV 5w-40 OR Mob 1 15w-50 Castrol GTX or blend XXwXXXX? might consider Schaeffers Your first hand favorite for 3.0L Toyota 3-VZE.