I have used spacer plates, i explored options of machining the heads and or the pistons or changing the pistons but met with a brick wall. There is not enough material to consider machining and changing the pistons would be seriously expensive.
The plates were made for me by Ferriday Engineering a few years ago now
http://www.ferriday.co.uk/
I wanted an intercooler/charge cooler but the decision taken was that it would restrict airflow too much, in this design there is also very little room to accommodate the cooler.
There is still the possibility of going down the water/methanol injection route but we are going to get the fuelling sorted first and see where we are at. Injectors are on standard duty cycle at the minute with the 1 bar increase in fuel pressure but I am going to be replacing with them as part of the remapping process.. The car still retains the original MAF.