no, not really..
Read the link you were given at the top of the thread.. an experienced oil expert not once iirc suggests using 15w, always 0w,5w or 10w..
15w is really thick so will make your car sound really queit from the engine bay which is a good thing, BUT..
Its soo thick it doesn't get to critical area's of the engine properly, therefore not lubricating effectively..
80% (i think) of engine wear occurs when you first start your engine from cold, by using 0w oil for example, as its thinner at low temps its circulates better stopping engine wear from cold.. a 15w, being thick, wont circulate very well therefore engine wear will occur..
I'd rather have a thin oil like 0w or 5w wich circulates really well getting to critical area's of the engine..
If its fully synthetic you'll be fine..
So read the oil sticky at the top of the Engines/performance section for more detail on the matter..