can anyone give me some advice on oem alloys i have 06 a3 sportback sport 140bhp currently got sport alloys 7.5j 17 et 56. I am thinking of 75j 18hz et54 are their any good or bad points to consider not sure what offset means i have read about spacers lowering would like to be able to just buy some nice alloys to jsut bolt on sorry if it has been asked before thanks very much