If the wheel only comes in a +45 in a 8.5" will i need to get spacers to have it reach the edge wheel well ??"Proper offset" is relative to the width of the wheel. If you want something that will fit under the fenders with no additional modifications/work, you'll want to stick within 10 offset of stock (+45 for an 8", +50 for 8.5" and +55 for a 9").
If you plan to add negative camber which I would highly suggest doing regardless for improved handling, you can run a more aggressive, lower offset wheel.