interesting info, possible parts swap thread.

[kDiqq_imp]

I would swap the whole engine, just for simplicity's sake. You could either put the 1100 throttle bodies on the 13 engine, or use the 13 throttle bodies and fab the ecu to compensate.. I dont think there is a head stay mount in there, so you may be able to swap the whole engine as a bolt on assembly, assuming there is enough room for the cylinder head under the tank.
Why would the valve recesses in the 1300 pistons be wrong?

So the valve PN is different so the size is likely different. But the big thing is the angle between the intake and exhaust valve. It's widened on 1100 for vertical clearance and looks. The cam valley is much narrower on the 1300.