You might want to reconsider the hardened seats. I've read a number of horror stories of an improperly installed seat coming loose and messing things up but I've never read one of an engine being damaged by using stock seats with unleaded fuel. The impression I've been left with by those who know a lot more than me is the only time you need to worry about damage is if you're working the engine very hard, near it's limit, for extended periods.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.