I do both.
Started with HM techniques and over time have made a couple mods (kill switch, mirrors delete), but I am definitely looking at more radical modding like a boattail or extreme weight reduction, maybe. I need to get a grill block and belly pan in place, but I'm waiting for this political season to end
Also, a PS delete is on the table, as well. Just need the time and motivation to do it.
I recently helped my sister-in-law empty her storage unit for her move to go back to U of M and as I was driving off, she was telling the other two guys that were there with us that I'd been getting 70 mpg by doing the things I have so far. One of the guys goes "I'd take my roof off if I could get that kind of mileage!" I laughed so hard about it when she told me later.
Both her and my wife were haters at the start of my hypermiling adventure and they've both stopped. My wife likes the extra money in our pockets, as do I. She still gives me crap about the way my car looks and refuses to ride in it, lol.