With regard for Number 2, the question is if you will notice a much better performance. You cannot always go by benchmark results, for they do not always reflect what you do on your computer.
I use the msahci driver and quite satisfied with the performance. If Intel had a driver that passed TRIM automatically and offered significantly better performance that I would see on my computer, then I would make the switch to Intel driver. But, benchmark results do not always mean you will see a significant improvement, and I am not obsessed with benchmark results, nor am I obsessed with spending lots of time experimenting. I bought an SSD for speed and enjoyment. I have enough speed, so now I am more into enjoyment.
With regard to your second Number 2, you do not use the Intel SSD Toolbox for defrag--you use it for TRIM.