Does anyone know what kind of gains are achieved going from stock 1200 efi to the 1250 with 10.5:1 pistons? [/align]

 

The performance gain would be negligable and there is a likely increase in oil consumption based on reports here. The 1250 upgrade is better suited for 883 owners that want to increase performance.

 

What will be my best options for maximizing performance without case boring? I am assuming just good heads, exhaust, pistons and a/c? [/align]

 

you already have good heads , just get them ported and polished , you could also have them decked and get a higher compression ratio but will need shorter push rods , also some high lift cams and an ignition moduale would be in order. if you are looking for gains in torque as well as h.p then a 2-1 exhaust will be your best bet along with a good high flow air cleaner.

 

very little compared to cost.

 

After doing the suggestions made by jwb47, would changing to 6 gears (I'm sure I've read on here somwhere that there is a 6 gear kit available for the Sporty, not from HD though, but forgive me if its an Urban Myth) not be worth considering? Wouldntit make better use of the extra performance the others mods had made?

Feel free to throw large denomination coins for any stupid remarks I make (I should be rich in no time).

 

How much power are you looking for?

In my opinion, if you have a 1200 rubbermount, then the best way to maximize performance is a new set of cams and a 2-1 pipe. You don't need any headwork as the stock heads will support 90-95 rwhp.

 

I can't see all the work and $ being worth it for the additional 50cc. I've heard people mention that the more you bore out the cylinders, the thinner the walls will be. Also, I assume it will stay more reliable the way it came from the factory. Spend the money on something more fun.