I don't believe DML is looking for power gains so there'd be no need for enhanced fuel or a reprogram. Even with both the reason there would be little performance gains on either the M90 PES or the previous TVS1320 APR kits is because they are already pretty much at their limits.
Heat reduction for retaining power under hard and persistent use (i.e. mostly on track) is where a water meth kit can be an advantage on either of these two kits. There are a number of PES clients Aquamist water meth kits specifically for this reason.
DML's target is carbon reduction. As I have explained to him via PM before I viewed his comments on this thread, as far as I am aware no one in the S5 scene has used water methanol to target reducing carbon build up. It would be very much a hit and miss project, a lot of expense using a full 8-port injector system that would have to include precise injection but there'd be no guarantee this is a solution to carbon build up.
DML, when I replied to your PM I'd forgotten there is a guy that started a similar project on a B7 RS4 which you can read up further information on here ....
RS246.com Forum :: The World's #1 Audi R, S and RS Enthusiast Website • View topic - My Water Meth Installation thread
In some knowledgeable circles there is a certain amount of belief that when changing out the manifold to add an supercharger you are also removing the flaps and this should reduce the build up. Personally I'm waiting to upgrade the PES kit to the Whipple and see how mine has faired (it was cleaned on the original install) before deciding if to try any way to keep the carbon away rather than just clean it once every 30k miles.
Ultimately water methanol is a far more complicated issues than most appear to appreciate. I'd suggest staying away from it unless you understand all implications of running it.