Tires and wheels size 2001 mustang gt

Hi, I currently have 245/45ZR 17 tires and 17 x7 wheels. Would like to put the biggest fat tire on all 4 not just the rears. Could you please recommend the biggest possible size tire and what wheel size would be appropriate? Don't want to stagger, but don't want them to hit wells in front. I'm a newbie trying to make a great choice for my sons bday. It's a surprise. Any recommendations for wheel brand and tire brand would be great as well. Price isn't a big issue. Thank you!!