Need help picking tires

[TreySmith]

What's the widest I can run in the front and back with simple modifications? I don't mind a little cutting and hammering but I am not going to tub it out.

I think 245/40/18 in the fronts and I am hoping for 315/35/18's in the back. Would I be better off with just 295's in the back? And what's a good cheap tire? Honestly I just want them for looks. Want it to look nice and fat in the back, I like my girls to have a little backside.

Here my wheel specs if it matters. I know a guy that has 315/17's on his car and he got them on their without modifications so I am hoping to be that lucky.

18x8, 4.75" BS, 1.5" Pad, 5x4.75BP
18x10, 5.75 BS, 1.0 Pad, 5x4.75 BP