Your gas mileage might take a dump when you add this extra weight/resistance too the mix.I appreciate your thoughts on that. I certainly would go for a 2015 Denali, but they're all at least $12k above what I can get out of mine. And mine is paid off and I've found I actually get much better gas mileage than the SLT I traded for mine. I'm also hoping I can do this conversion for between $4-5k. And being retired allows me with plenty of time on my hands, so that's a plus. Thank you though and I hope you stick around to see how this project turns out!