it cost me $5000 to convert my (VZ) wagon to manual, that was just parts alone, if you are paying someone to do it and hasnt done any research into how to change the wiring and do some computer trickery youll be pissing atleast 1000 bucks to get it sorted,
breakdown, for me,
cheap conversion kit $1500
clutch at heavily discounted price was $1500
new tailshaft at right length, $900 (cant cut and shut or swap pieces anymore - excpet some)
other ancilary bits and pieces, $600
if you have a 175 motor and its and it in a sedan or wagon you will loose about 10-20 fwhp as to get it to it to work somewhat normally youll need a holden tech 2 and vcm suite, holden to re-program the car to a sv6 and vcm suite to disable the fault codes for the oxy sensors and variable valve timing, as when you program it to the sv6 it loads the 190 software, it has exhaust vvt and different oxy sensor setup, thus with the 175 missing it has a dummy spit and shuts down both systems, you can program it as a ute, but your fuel guage stops working correctly, - only goes to 3/4 ish when full and looses about 30L on the guage, so telling you that you only get roughy 200km's to a tank around town,
to do the conversion properly you need a level 1 car (calais is level 3) a 190 motor and the 6sp box, dont hold me to it but it might work on a level 3 car if you cut and shut the dash wiring to suit