Tire size versus ET's street radials

WOW Great times for E70's!
At the moment this car is my daily driver, it has a balanced n blueprinted 318 with a cam that is similar specs to the '69 340, mild port and polish, headers 600 vac sec, good fuel economy but doesn't have much pull below 3000rpm then it really picks ups.
When I get my D100 on the road, I can go to town on the dart. Put the 4.11 suregrip in it and then look at building another motor if the wife allows LOL
Thinking about a stealthy 318 stroker that looks stockish to an idiot. =P~