Hi Steve
I think you will be happy with the performance of the speedmaster, or the America. I have the America and ride two up quite a lot with the Mrs, who says she falls asleep on the back. Not like a Hardly they are very smooth.
I get around 150miles before I think about looking for a petrol atation (IN THE UK REMEMBER) as for touring very comfy it's like being sat in an arm chair.
As for bolt on products, maybe not as many for us at the moment but we have a good few places that are changing this. The performance can be increased by changing out the pipes and rejetting and if nescessary you could fit the BB kit.
I'm sure someone else will chime in with other bits n pieces I have not mentioned. Safe riding
