I have purchased many thousands of dollars of suspension items form Mustangs plus, they sell good stuff, but they are not the only suppliers, so shop around for prices, sometimes you can get the same thing for a little cheaper elsewhere. One thing I did I waited till Mustangs plus offered a 10% price break on larger orders, or buy suspension kits instead of individual components. Be sure you know what you want before you buy, what wheels and tires, how low you want your car, how stiff you can stand the ride, some mods dont work well together, and IMO stay away from the negative wedge kits.
1-In my case it would lower the car even more than it is, that would be to low.
2-I dont like the camber that is required, personal preference.
3-I did it my way and it works great, dont need a negative wedge kit even with the vintage 45`s.