Trying to find some way to do this. I have avery fat laptop, ..............but need something else I guess

I'm still new to sonar but in cubase you can map note information from an external device into a command for most anything.

But it is positional in cubase, not sure about sonar.

So if you set it up to control things in Guitar Rig and it's the 4 plugin on the bus then you add another plug in and make GR the 5th position you have to reconfigure it.

You need to find out what messages the pedal is capable of sending then find out what messages the plug responds to etc.

A box like is made by midi solutions can convert one midi message into another one. Like my yamaha pedal sends program changes or CC's but the MSbox converts that to notes which cubase converts to commands.

I use it to change cursor tools.

Your info is great, but Sorry, I wasn't clear-my bad. I saw a guy at a small club here using guitar rig as his , well guitar rig. He had a small mixer, laptop and small PA. Guitar sounded great and I watched closely, there was not perceivable delay at all on the guitar. NI sells this mobile Guitar rig (I already have GR4 full) wjioch come with a small USB interface for the guitar. 
Wondering (and wanting to try this) how folks do this without a delyin the signal.
Thanks

  If your computer is fast enough you should be able to get the latency down low enough to be unnoticeable without any dropouts. Latency shouldn't be as noticeable in a live setting as compared to recording too so that gives a little more wiggle room and to keep CPU usage down and you can leave the "Hi" button off because the difference won't be as apparent. As far as the controller... MIDI is MIDI. If the parameter in GR you want can be assigned you should be able to control it with whatever you want. However the GR controller is probably the easiest if you can afford it.  

  That said though, TH2 is probably better live for multiple reasons but the main one being it is less of a resource hog than GR which in theory should allow you to get your latency values lower. Obviously it is fully MIDI assignable too and although I've never assigned either program to a controller the TH2 way looks a lot easier. TH2, IMO, also sounds a lot better and will likely react more like a real amp on stage.  
There is a video on youtube of a guy showing how the TH2 MIDI assignment stuff works. Just search "TH2 MIDI" and it should come up.

Cheers.

I know all about midi ,my question is\was all about the latency. I also prefer GR over thd2-.
I have and use an AxeFXII so my question is looking for a halfway decent backup and I would ratrher the backup wasn't more to carry. I 'll test my laptop with GR4 full and see wheere i get. NIO instrument sell a s mobile interface, (not the kontol rig).
That is what I am curious about. Getting the signal in with the least latency