Does installing a nose cone on a trs help in anyway or is it a was of time and money ?

It's a waste, unless your going really fast- makes it more steering sensitive

I think the general thinking is anything above 80 mph and you will notice a difference.

I think it really depends on the setup. I think I remember some people on here actually loosing speed above 80 when they added a cone. However I do think that most benefit from it above the 80 mph like Kaama82 said.