Remember the taller the tire the more rubber you put on the ground too, it's not just the width. As the car plants the rear the tire spreads out lengthwise, that's why all the 10.5 tire cars run 33 inch tall tires. For that you need to stretch the wheel opening and install full fledged wheel tubs, not just mini tubs.
Let's face it you are young, and I presume you don't have 3 screaming kids that need to be fed and clothed, nevermind no mortgage and no wife that's always complaining you don't spend enough time with her, or help out around the house and with the kids, and how you don't meet her emotional needs, etc., etc. You get the picture. If you build the car the right way now you'll have a car for many, many years to come that you can do engine upgrades and stuff to later, but the chassis will always be there for you. Unlike the wife. :)