I typically get 400 miles to a tank of Tesco 99, 420 is about the best I've done when driving a bit more miss daisy style, but as I like to go quick I don't do it too often :)
Never knowingly reset the ECU but after nearly 10 years of ownership it should be finely tuned to my heavy right foot by now :D
Always liked the Goodyear GS-D3 tyres, which I replaced the Dunlops with after about 3 years from new. Went for cheapo ones on the front earlier this year as I wasn't sure how much longer I'd be keeping the car - definitely not as good grip-wise as the GS-D3s or the newer Goodyears which I have on the back.