It is your car, do what you want. However, why? That is my huge question. Are you really doing all of this for looks(which is ironic to most of us)? Maybe you should have someone photoshop your ideas, before you try it. A photo rendering of your plans is often a very good idea and can save you from making a huge mistake. Also, a diffuser(or any aggressive aero) on a non track car is just retarded.
Tow hooks are stupid too. I only had one because I had to. Now I have a tow strap that tucks neatly behind the bumper. To this day I don't know why people add tow hooks for looks...Ill never understand that kind of stuff. To each their own though.
Hit up GPR Auto, that's where I got mine. The only down side about the strap is it can be cut, so chaining your car to a pole isn't as effective anymore... Sucks