8mm
M12 x 1.25 x 40
Not sure about the hole but the stud size is M12 X 1.25
size is M12 x 1,5 dont know the length of the bolt though
M12 signifies that the shank is 12 mm diameter. The length will vary. +++ Another tip: The A/F size of a standard M12 bolt or nut is 19mm, so close to 3/4" that the latter spanner will work - but be aware that this is the only co-incidence between metric and inch-based fastenings; and the M-series proportions don't follow a very consistent path!
M12 1.5mm
M12-1.50
M12-1.50
http://www.gmpartseast.com/pontiac/components/2002-grand-am_suspension-front-mn060600106-ld9mn52nw69.html or search the google "M12 X 1.75 X 35 10.9" it's size: M12 Thread: 1.75 Length: 35 Steel strength class: 10.9
M12 x 1.5 ( Metric ) thread
Find a gunsmith.
Well presuming the bolt has a hexagonal head then the German standard is 19mm across the flats of the head and will require a 19mm socket but you may well find that the ANSI/ISO standard applies which will mean the across flats dimension will be 18mm and will require an 18mm socket. +++ Whilst I accept the American car industry might have its own version, be aware that almost all commercial ISO-M12 bolts and nuts, and the reference charts, have 19mm A/F hexagons, NOT 18mm. By co-incidence a 3/4" A/F spanner will fit a 19mm A/F hexagon but this the ONLY such coincidence between the inch-based and ISO-Metric fastenings.