Regarding load ratings, you just want to make sure the tire's rating is high enough for the car you're putting it on.
I've used many XL rated tires on my MS3.
http://blog.tirerack.com/blog/miles-of-smiles/xl-vs-standard-load-tires-what-should-i-do
Yeah that's another thing that sucks about the stock pads. There is no need for them to produce that much dust relative to their stopping power... Only pads I've ever used on this car that dusted more were track-only pads.
Stoptech Street Performance pads (from what I remember) were very similar to the OEM pads in bite and modulation and cost $80. I even tracked the car on them once (on sticky street tires) and they held up reasonably well for a street pad (though I wouldn't buy them specifically with tracking in...
I have a Speedhut electronic boost gauge that has been thus far flawless (I've had it for almost 3 years now).
Looks great and has pretty robust hardware/parts to boot.
I wouldn't hesitate to recommend them based on my experience.
Yeah... As I'm sure you know, the caliper temp is probably more important as a data point, as that is what is directly transferring heat to the fluid.
You might want to look into some temperature-indicating paint for your rotors and maybe some stick-on temp strips for the calipers, as those...