Brushless advice please.

[superstu55]

Now about to buy a new CAT SX2 and at last I'm going brushless,

Will be running a 10.5T motor indoors & just after a bit of advise on what speedo, not necessarily after the most exspensive just something adequate,
so far Ive been looking at the speed passion gt 2.0
speed passion gt pro 2.1
lrp spx stockspec 80710
any of these or something else?
and do I need sensored on sensorless?

And finally what make of motor? a couple of people ive spoke to have said go for a GM?

Any advise much appreciated. Cheers