I am specifically thinking about M1 15W-50 here. It seems to me that this oil could be an excellent choice in hot climates for summer driving and towin, especially in GM V8 pushrod engines (LT, LS). I do understand that you probably want to run it only in summers and not winters. I have seen of no evidence that anyone here using the heavier viscosity has had increased wear as a result. What in your opinion are the drawbacks of let's say 15W-50 compared to 10W-30 or 5W-30? It seems that M1 15W-50 has helped a number of people here to quiten down their mechanically noisy engines without causing any increased wear. Opinions/experiences please??!!