Was just about to smite you down for claiming such things.

Tbh i would have an 16v as i feel they are the better car to drive and own. Plus a 16v will quite happily drive in 5th at 2500rpm and not give you a worry and return good economy.
If you now the right places, things are not that greatly varying in price and they are both just as easy to maintain as each other.
Petrol, humm depends on how you want to do it, i personally see no gains whatsoever from running on optimax, i do however see the hole in my wallet get larger. I just place a Petrol treatment in the tank every few tankfuls and it keeps the motor running sweet as a nut.
Therefore my onus is on 16v.