Brake upgrade questions

[steveb@falcon.kla.com (Steven Buchholz)]

When I found out that I had been sold the wrong replacement pads for the 
front brakes on the urQ, I decided I'd see if the dual piston 5kT calipers
that I will be installing soon could be used with the existing rotor.  I
found that when I installed the carrier it rubbed on the urQ's rotor, which
implies to me that the rotor on the urQ is larger than that on the 5kTs.  
Since braking effectiveness is a function of swept area (given materials 
and forces are otherwise constant) does this mean that the urQ has greater
swept area?  If this is true, what real benefit do I get from the fact that
I have a larger pad and the dual piston caliper?  I can tell another down
side to the new calipers, and that is that they are considerably heavier
than the originals ... increasing unsprung weight.  The one thing I like 
about the new calipers is that the pad is held to the caliper, which means 
that there will likely be less friction when the brakes are off.  Any re-
sponse on these thoughts/questions is greatly appreciated!

One other comment is that I was quite surprised to find the right front 
pads were nearly gone while the left fronts had considerable material 
left.  In both cases the wear was consistent on the inside and outside 
pad, both lefts good, both rights gone.  I have never noticed any pulling 
under braking, the car wears tires beautifully (probably the most even wear
I've ever seen on a car ... even the guy at the tire shop commented on them).
The only thing that I do notice is that under max braking the left front 
tends to want to lock up first.  Any thought or suggestions here?

TIA!
Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)