Ressurecting this slightly dusty post with a follow-up.
The cost of performance is steep. And the farther you go, the more difficult it can get. My car is now very temperature and octane sensitive. Not quite what I would have expected considering the work I did in the last 25 pages of this topic.
I've had to go back to last year'* heavily-drilled thermostat (on the left in this pic, the one on the right came out tonight). This is an INTENSE 160. Keep in mind I have a 10% underdrive water pump pulley and a brand new water pump:
I have to keep this sucker cool to stay in the power. The good news is my radiator core looks brand new, in spite of 125,000 miles:
I can tell you that with either a cold or cool engine (below 160 degrees on the gauge) or 96 or higher octane, this car has MAD power. With both higher octane and cool temps, it'* even more thrilling.
I'll also be changing fuel injectors soon........
In a nutshell, the 93 is noticably quicker than the 95 when cold. Even more so with higher octane (both cars on 2.5 pulleys, SLE running the Zilla'* top end from last year). But once the Zilla heatsoaks, the two cars are neck and neck. This is the price of performance for me. Was it worth it? Sure. I went places I never thought the Zilla would go. And the SLE is benefiting from the work now as well.