welcome to the forum,
sorry to tell you 4x100 wheels wont fit, and you would want close to +10 to 0 offset for them to actuly fit and need to look at the guards,
any thing out of a celica is an upgrade but i would suggest some ra23 or ra40 struts
cusco diff center wont fit unless you get a t series diff and put leaf mounts on and drop it in the car,
just get yourself another set of leafs and flip some, i can help with this if need be, will stiffen it up and lower it at the same time,
7k sounds like the G-O
quick racks are avalible but it would have t be from a dinky die jap model one and really isn't worth the hastle.
look forward to seeing your car around and hopefully on a cruse when we can work one out