I'm an OK skier. Live in the Midwest so don't ski powder and there aren't a ton of bump runs to practice on (learning to ski moguls is an aspirational goal). I'm NOT versatile, but can hold my own pretty well on groomers in all conditions, and have learned how to bend a ski and carve pretty well. Anyway, I've had a pair of Elan Wingman 86cti's for almost four years, which have been really fun do-everything skis. Two things over the last couple years, though, made me want to get a pair of "real" slalom skis: 1) our big hills are 500' tall, so maximizing my number of turns is a benefit, and 2) watching race kids from the lift zip their skis back and forth across their bodies looked like so much fun!
This past fall I bought a new pair of Head e-sl's. I know...they're not FIS, and they're not even the pro model, but they are short, heavy, stiff, and have a 12m turn radius. As far as I can tell, they're no joke, and here's the point of my post. If you are already a competent skier, but want to learn how to really manage balance, tip pressure, ankle/knee rolling, timing, and body movement, do yourself a favor and get a pair of this type of ski. If your edge angles aren't similar, they will let you know. If you get in the backseat while carrying any type of speed, they definitely will let you know when they try to shoot out from under you and launch you into next week. They are the most fun I've ever had on skis, and they've made me better because they are so good at revealing technical flaws.
TL;DR- if you've already skied a bit and want a coach attached to your boots, buy SL skis and start ripping short turns.