Which T43 is closest to my T42?

[rocketman]

I'm trying to get a handle on which T43 is the closest in specs to my 15" T42 model 2379R9U. I'd like to know what the improvements might be over my T42, from what I've read there might even be a step back like using integrated graphics instead of the dedicated video card and perhaps less battery life. Can someone let me which T43 this would be?