IETester hooking is not perfect yet, but the engine is the correct versioned engine used on each tab. You can find more information here :
http://www.my-debugbar.com/wiki/IETester/HowDoesItWork
Regards.
For IE debugging you can use DebugBar (http://www.debugbar.com/) and Companion.JS (http://www.my-debugbar.com/wiki/CompanionJS/HomePage) that give dev tools for developers : DOM inspector, HTTP viewer, JS console, etc...
Hope this helps.
JFR http://www.debugbar.com
IETester hooking is not perfect yet, but the engine is the correct versioned engine used on each tab. You can find more information here :
http://www.my-debugbar.com/wiki/IETester/HowDoesItWork
Regards.