Putting 19 inch 2007 porsche 911 turbo wheels on 2001 like car

My 2001 Porsche 911 turbo has 18 inch wheels of different widths than my new wheels from a 2007 porsche 911 turbo. Will spacers be necessary? The 2007 wheels have no tires on them now but had rear tires sized 305/30 19, will these tires fit on my 2001 turbo or should I go to a slightly smaller tire in the rear? If I do go to a smaller tire in the rear will that eliminate the need of spacers or do they have anything to do with each other? The front 2007 wheels came with 235/35 19 tires, will this size tires fit on the front of my 2001 turbo with the 2007 wheels? thanks for your help.