FSX depends more on a fast CPU than GPU. According to this list
http://www.cpubenchmark.net/cpu_look...50+%40+2.67GHz
your i7 quad core 2.3 Ghz 3610QM scores 7533 points, while my i5 2500@3.3GHz scores 6418.
So, when I can run FSX with all these addons, the complex aircrafts I use, airport scenery and REX and Active Sky, then I think the outlook is good for ya. With the default planes you probably can run REX with frames at 30 (if you cap them externally as recommended). I would be very surprised if you get problems. - But i must make a disclaimer, of course: I cannot guarantee that you will be fine. Systems are specific, and what works for me maybe will not for you due to some minor specif difference that causes problems. But I think the chance is very small only.
BTW, what resolution do you run at? Just curious, some addons are optimised for certain higher resolutions that may be not present on notebook-size screens. REX not one of them, however.
One thing, however: FSX is not optimised for making use of multiple cores, it is programmed for using once CPU only. I see on my system that I have two cores maxed out,
with the other two cores being ignored. The list I posted probably takes into account
full quad-core usage. The two cores used on my system are probably one for FSX, and the other doing all the background tasks of Windows, online weather data exchange and such. If that is true, my system
maybe runs FSX faster than yours, since my single core GHz is higher than yours and the performance of your in principle superior quad core does not fully weigh in, since only one core is used on the sim. - I do not seriously think this to be an issue, but I just wanted to mention it.