That's why I let my 117 LRS go and bought a Rocket. To take the Harley out to 128" and do all the mods necessary it would have cost me nearly as much as I paid for my used one year old GT with 3K miles on the clock. And I'd still have been 20 bhp and 20 lb of torque down on the Rocket.
If I'd had the money I'd have done it anyway though. There's nothing quite like a big inch Harley.