Thats a good tank - Now your "mojo" is back, set a target - say 35 and go for it. It may mean not going for the front of the queue or always overtaking on the backroads but then again think of the money saved and what you could do with that - maybe a meal out at the end of the month with the Mrs (woo), or a day in a playpark for the kids or something maybe your and Mrs D0s were saving for.
All more important than going fast IMHO.
I would give the mods a miss TBH, although if you want I (or indeed 320, or any of us Europeans with our free healthcare and lazy lifestyles...) could see if we could find what you need. I have to say 323s of that vintage are rare here because of rust - we salt our roads in winter.
Good luck.
