K-Tec RSTuner

Right,

Is this any real benefits from a self tuning module such as the one offered from K-Tec like the RSTuner.

Any gains in terms of performance?
Can it adjust the ECU so that running on VPower (for example) will see a better outcome in MPG?
Will it adjust the ECU so that the engine revs to 2k RPM for a decent warm up?
Those types of gain etc ...

I've had a search and couldn't find the answers I'm looking for.
If you've had any experience that'll be great.

Thanks.
 
Thanks for the replies.

Is there any particular place which is recommended for a good live map?