American Muscle "Mustang" wheels

The 30mm offset will be pretty close to fitting ok. This is going to be tiresome advice but take a look at what you have and measure how much clearance you have, then look at the specs and see how much the new wheel/tire combo will change the position and determine if it will still work. It's a headache but it will save you a lot of money. There used to be a tool for this on line (it was called the "Rims 'n Tires Calculator" or something like that) but I believe the website is gone now.

Along those lines, you'll want to watch your tire outer diameter. Tires that are too tall run the risk of rubbing, especially in the lower front corner of the wheel arch. Crank your steering over and take a look at how much clearance you have currently. This problem will get worse if you run more caster than stock. Just as a reference...not to be taken as gospel; I have 5* of positive caster in my setup (much more than most cars here) and I had run a 245/40/17 on a wheel with a similar effective offset which was just shy of 25" (a little shorter than what most would run) and they cleared everything fine.

You'll also want to watch the center bore on these wheels In addition to what Tsully said about the cap height requirement, these brakes need a 73mm bore which seems to be larger than what most cars call for. For example, the stock Mustang wheels usually needed to be machined-out to fit our cars...but I don't know about these aftermarket wheels.

Good luck!