Calliper overhall and brakes query

[jabriel]

How much should one expect to pay for an overhall of all 4 callipers? (In case its relevant, the car is a (250bhp) 944t)

Also, are 928gts brakes better than the standard (250bhp) 944 brakes? And how much do these cost?

I'm may have to overhall the brakes later this year so was wondering what the better option is.