I purchased an '04 GMC in March that I will be using for towing an RV. It's been suggested to me at RV.Net that I consider getting gauges like pyro, boost, trans temp, etc. Are these worthwhile for towing? Where would I look to purchase this sort of thing and who would install it? Should I be going back to the dealer, seeking something online with an install by a private guy, going to a place like Pep Boys, or what? Thanks for your thoughts.