knappster,

My system shows your stock wheels are 7.5" wide with +44mm offset. This gives them a 6" backspace. Add your 1.5" spacers and you basically have a wheel that is 7.5" wide with a 6mm offset (4.5" backspace).

These wheels are 9" wide and have a -12mm offset (also 4.5" backspace). This means the back edge will sit the same as your current wheel/spacer sits but the front edge will stick out about 1.5" further.

Hope that doesn't sound as clear as mud.