Finally set the timing on my $600 Miata and the whole weekend flipped

I bought a 1994 Miata back in March for $600, mostly because it ran, kind of. It had a bad miss and the guy I got it from swore it was the plug wires. It was not the plug wires. For about two months it bucked and stumbled anytime I got near 3 grand, and I just drove around it, shifting early like a coward. Then on a Saturday morning I borrowed a buddy's timing light and found the base timing was set at like 4 degrees instead of 10. Somebody before me had messed with the CAS and never put it back. I got it dialed in, took it down Route 9, and the thing pulled clean all the way to redline for the first time since I owned it. Spent the rest of the day just driving with no real destination, which I never do. Anybody here ever buy a car where one dumb adjustment made it feel like a totally different machine?