Hi Kurt,
Can be fairly straight forward, but it depends on what you use for a throttle control and what arrangement you use for air into the carb.
If you use the Aerovee throttle and flex cable you may have to be a bit creative in getting the pull cable out of the top of the carb.
The alternator X frame gets in the way of routing the cable.
If you use a direct vernier type cable it needs to come underneath to push open the carb. This can have some routing and stiffness issues.
Brian Heinmiller has a good write up on how he did his installation using a vernier type control and a reversing bellcrank to pull open the carb slide.
Also some good notes on tuning.
http://www.heinmiller.visionhost.info/c-gsbh_00001f.htmI used the aerovee throttle and flex cable. I had to fabricate a curved cable guide out of the carb top to get past the X frame. Without it, the cable was fouling the X frame.
I also retained the ability to carb heat, (Sonex say not required) however I have used it in suspected ice conditions and on long descents... better to be cautious I think.
I made a small fibreglass elbow with flow-vane to take air from the scat duct to the carb and get around the engine mount.
I have some details of the carb install in my running blog at
http://sonexaus.wikispaces.com/Tony+%28Richo%29+Richardson+Sonex+813 you might have to scroll down a fair way to get to construction details. (April 13)
Cheers Tony