carb vs efi throttle response?

Throttle response can be to a few things.. but i think mainly to how far the carb is from the inlet.
You'll notice most carbs (especially twin webbers or quad throttle bodies giving each inlet its own butterfly and injection of fuel) its situated very close to the engine itself. So its a short path for air to go into the carb and then in to the engine.
 
With turbo, supercharged and standard efi systems they tend to more use a single larger butterfly to accommodate all of the inlets (although i know Nissan Gtir's have turbo and quad throttle bodies!) which is spaced considerably further away from the inlet than that of a quad carb or throttle body setup.
Also with forced induction your waiting for air to run through the engine, through the snail (on the exhaust side) to turn the compressor which then forces air coming in through the air filter then through the butterfly and then into the engines inlet... which is a huge path to travel. Hence the name.. Turbo lag!
Supercharged are not so bad in relation to a turbo as they run from a belt so they are not waiting for air to turn the compressor.
 

1: yes, but it would be quad throttle bodies then a plenum just feeding cold air.. (ir doesn't need to be sealed).. You can't get any closer than throttle bodies. If your looking for the closest.. AT Power do direct to head on certain engines.. = butterfly as close as it can go to the inlet of the engine.
2: no, chargers don't get any lag due to the belt of the engine rotating it as the engine revs (i.e.. from basically 2 revs up). If the carby/efi was in the standard NA position it wouldn't improve or degrade.. it would just be the same response but you'd have a forced air driving the engine further to its prime rev performance sooner = more revs/fuel/air = more hp.