the stock rear offset is 22 as far as I know... with 45 you will need a 20mm spacer..

the front stock offset is 35mm but since you are using different width I suggest you take a look here http://www.1010tires.com/WheelOffsetCalculator.asp

to see exactly what you will be going.. try to get both wheels as closely alligned as possible.. even if it means that they will be pushed inward or outward some...