tires and wheels question

[95mustang_gt]

well im going to be getting some wheels and tires,i got them for a good deal.The front tires are 255 45 18 and the back is 285 40 18.The offset is +24mm and backspacing is 6.19".i think the guy said 50mm.Im trying to avoid wheel spacers,i heard and read stories about them.What can i do to get them to fit?Any tips will be helpful.If i have to run wheel spacers what should i worry about?

thanks
Jesse