The stock strut housings are fairly tall. I'm not entirely sure how low he wants to get his car, but getting much lower (as a 205 50 on a 15 has a fair amount of gap) will cause the stock sus to bottom out or hit the bumpstops. A lot of people get coilovers to get the car lower and change handling characteristics, yet still retain shock travel. I'm not saying that its wrong for anyone to go with a spring and shock combo, coilovers can generally go lower without sacrificing as much.
In terms of the phrase tucking tire, it's pretty widely used in the fitment scene as getting the top of the tire into the fender at static height. I think it's fair to say that you and I use different lingo.