Is this a hairball operation?  Can I plug the vacuum lines going to the diaphragms?  This would seem to be the only tricky part.

Its actually easy, you may need to get the cables taken care of. Only tricky thing IMHO.
Cool.
Buddha.

The carb boots are different. I suggest you change them. It can work, but fitment is a little different. When you change carb boots, also put in new o-rings or you will get an air leak.
Air box boots are different because the air intake of the carbs is a different size.
Throttle cable will need to be changed - probably - but might work.
Choke cable must be changed. It attaches differently to the carbs (left rather than right) so needs a different carb end.
Extra electrical stuff can be ignored.
Vacuum line to PAIR can be capped off. Otherwise all vacuum lines remain intact and in use. Connection  to the petcock is same but comes off of right carb and vacuum line cluster.

If you want to go the whole way like i did. Replace the carbs, wiring harness, hand controls, and gauges, and then kick stand switch, and gear switch. Then everything is accounted for. Or you can do just the carbs and run one throttle cable to it and a newer choke cable. Up to you.

I find the 89-00 carb booth better than the 01+, I actually dont like new carb boots you get @ stealer regardless of the year. The 89-00 has updated to the 04+, and the ones you get now are really really crappy. Some chinese junk.

Cool.
Buddha.

The carb boots are different. I suggest you change them. It can work, but fitment is a little different. When you change carb boots, also put in new o-rings or you will get an air leak.

These are the boots to the manifold?

Air box boots are different because the air intake of the carbs is a different size.

I have the K & N lunchbox rig and have ordered new jets as specified on GS Twins.com

Throttle cable will need to be changed - probably - but might work.

Looks like it's a single cable setup, unlike the European models, so it should be ok if the ferrule wheel is the same size, otherwise I can probably swap the wheels out.

Choke cable must be changed. It attaches differently to the carbs (left rather than right) so needs a different carb end.

Different ferrule (cable button) size?

Extra electrical stuff can be ignored.

That's what I figured if the diaphragm chamber inlets are to be blocked off.

Vacuum line to PAIR can be capped off. Otherwise all vacuum lines remain intact and in use. Connection  to the petcock is same but comes off of right carb and vacuum line cluster.

Apart from the lines that go to the PAIR, there is a T off the line to the fuel pump that is a bit of a mystery.  It doesn't seem to go to anything on the carbs and I don' t know if there is a gizmo mounted on the 2008 bike frame that it goes to.  Also There is a small cannister coming off a T at the top of the carbs, looks like its analogous to the valve cover vent tube on the early models, and there's a larger, frame mounted cannister off another vacuum tube.  I'll leave that stuff on there and tuck it away somewhere.

Thanks for clarifying this for me. 

We don't have a fuel pump. We have a vacuum petcock. One line goes there. Newer carbs have a small canister that is bolted to the round cross member of the frame (could go anywhere). That's a vacuum reservoir so leave it. Only thing that gets capped is ONE line off of a T that goes to the PAIR system. Everything else stays intact as it is.

The lunchbox connects to the carbs. Remember the air intake of the carbs is a different size. I recall larger on older carbs.

Choke cable has a 90* bend at the carbs. Older one had a 45* bend. Older choke cable probably will not fit properly.

On mine I had to fab a longer throttle inner if I remember.
Cool.
Buddha.