There should be an option to not lose your current downloaded tune when browsing for a new tune - ie, if you’re running a downloaded tune and it just doesn’t quite work, you go to search for another one and you’re automatically de-tuned to “stock” parameters, giving you comparisons between THAT and your new prospective tune. There should be an ability to keep the downloaded tune installed while browsing for the next tune, and being able to compare graphs and stats between those
(or, additionally, a selectable toggle between multiple tunes that you can compare side by side on a different screen or something, although I’d expect that to be a lot more of a programming hassle)
Once a tune is selected, THEN the existing tune is “uninstalled”
“Hey Bob, yeah, I need you to put the stock camshaft back in while I shop for one that’s a little better than the one I’m running now, because that totally just makes sense…” 
It would also be nice to see a preview of what the actual tune “looks” like, are the wheels ugly? Is there an obnoxious blower blocking the windshield? Is there a 4x8 sheet of plywood hanging over the rear decklid? Gotta buy it to find out.