Can thicker oil like 15w-50 damage things if used in winter time?

LOL i own a 95 gsx with a Holset hx35 wheel(WH1C).. Runs 12.60s at 109 anyways. The main number to look at is the w number.. Another thing to look at is how far apart the winter number is from the warm number.. That means they added alot of addatives to the oil to get it to that low viscosity.. I think you should switch to the 10w40.. Thats a better number to run at.. I run 15w40 in summer but don't drive it in the winter... Are you apart of www.dsmtuners.com?? You will learn alot on oil and more about the car on there... Good luck man.