No car "needs" a 4-wheel alignment if the rear (IRS) isn't wearing the tires unevenly it hasn't been "tweeked" in an accident, and a friend following your car doesn't report that it is going straight down the road "doggie style" (car not aligned with direction of travel). IMHO I think a lot of shops screw up rear alignment (there are notable exceptions), so if it ain't broke, don't fix it.

Personally, if the above parameters are OK, I would just have the front rubber bushings checked (since those do affect alignment) and have the toe set properly. If they do it right, your steering wheel will be centered (someone recently posted that post-alignment, theirs was off) and your front tires will wear perfectly.

As for my basis for these statements, my dad operated an alignment shop for 30+ years (and I spent too much of my youth there soaking up practical knowledge).