I personally don't have the equipment to quote logs and prove improvements with data, however; from reading this thread I believe I've rectified a fair few niggles I've found.
Mainly hesitations when accelerating, not smoothly pulling through the powerband and minor missfires. Fuel has exclusively been NPD 100+ or BP98 where 100 is unavailable
Firstly, I sealed the cracked intake box the day I picked up the car. With regular maintenance I've been cleaning the throttle plate for carbon build up.
After your suggestion, I checked all header/cat heat shields for security and found a couple brackets loose and vibrating. New bolts and/or nuts secured those. Small improvement to engine running seemingly felt.
More recently I replaced all spark plugs with NGK ILFR6B plugs. When doing this I came across 2 further issues. Removing the headers to jack up each side of the engine revealed a loose header nut causing an exhaust leak, couldn't hear it at all though. Cleaned up all surfaces and seems to be okay
Secondly, someone previously has broken some of the locking tabs off the coil wiring plugs. Their solution was to fill the surrounding area of the plug with RTV, now rendering the plug useless. This also seems to be causing the plug to not be seated 100% of the way home on the coil. Whether this is causing irregular coil performance I don't know...
After fixing the exhaust leak, new plugs and an ECU reset the engine performance feels like it is improving further. Again I don't have the data to prove it, though it certainly pulls harder and smoother, more consistently as well