Hi I have a 2011 silverado 5.3 vortec that I do a fair amount of towing with. I think weight wise I am well with in my limits of towing (7x14 enclosed with 4 harleys max - about 6k loaded) is the biggest load I will tow. It does an okay job, but seems to struggle to maintain speeds over 60mph and expecially on hills. I don't think the load that I am trying to tow necessitates a diesel, and I have heard that the more horsepower that the ecotec 5.3 puts out seems to help the truck quite a bit in the tow department. Are there any bolt ones that I could do (headers, tune, exhaust) that will make my truck more comparable to a new one? To be honest I am suprised that chevy's main engine for these year trucks are down a minimum of 40hp when compared to the other trucks in that category for the year. Any advice? I really don't want to have to bite the bullet for a new truck becuase I find it kind of rediculous that the truck struggles to tow even 70% of the advertised tow ratings. I do use WDH when towing this amount of weight and keep my paid load numbers way down when possible. I have checked all weights and they are all in within tolerances of what the manual and internet seems to suggest. Not sure if I am asking too much of the truck or what?? Thanks in advance!! Help me not be the slowest tow vehicle on the road please! When I am towing this load it is for far distances (CT to Florida) so the more enjoyable I can make the ride the better.