Hi if anyone could help me would be appreciated im looking to do a stud conversion on my polo 9n3 gti would any one know the size of the stud i would need would it be either m12 or m14 by 1.5 or another size thanks

The standard bolts are M14 x 1.5 x 27 so you will need make sure your new studs have at least 27mm of thread from the face of the hub surface

I used the Bimecc studs m14 x 1.5 and i think i went with the 63mm total length ones. Length really depends what you want to do with them, but the 63mm ones allowed me to run id say maximum 20mm spacers safely.