Best Performance Upgrades for Little Money - Here's My Vote

Well I couldn't think of anything, until, I remembered my fuel filter. It wasn't that cheap to buy, but considering that its been on there since about 2000, in terms of cost per year, it ranks right up there with my Optima battery, which has been in there for about the same length of time.
The filter is an EFI prefilter, with one hose barb and one tube fitting. It's about 2.75 x 5, as I recall. I installed it at the back.I found it in a jobber catalog, in the picture section.Sweet filter.
And then I remembered my TTI system with dual Dynomaxers and 3 inch all the way.. Its been on there since 1999, so it's down to about $75Can per year now.
And then I remembered the GV....
Ok so I'm not a super good bargain hunter.I'm more into the big-picture, kindof guy.
In spite of the mega-thousands of dollars I spent bringing my car back to life, two years ago marked it's official parity with any of my newer cars in terms of years of service per thousand dollars invested. It could totally disintegrate tomorrow and I can safely say it was the best value in a car that I ever owned.
But you just know that ain't gonna happen.A fresh set of quarters and wee bit of paint and away we go again.