That'll be an interesting addition to his lineup. I like the Koni/Eibach combo that I run but I'd really like a nice set of coilovers when I grow up though.
I did a ton of research before pulling the trigger on mine. I chose Swift because they're the stiffest out of most of the options, have a linear rate (which is actually really important for consistent handling, especially if you have extra stuff in your car), have an extremely good rep in the racing/auto-x world, are made of lightweight material, don't sag over time, and show extremely consistent spring rate throughout their range of compression. I also like that they use the same spring rate for the rears even though we have like a 65/35 weight split. That actually helps bring the rear around better and addresses understeer inherent in our design.
Koni Yellows were a no-brainer. I only went with the fronts, though, because you can easily adjust them while on the car. Bilstein B8s were my choice for the rear because I don't have to worry about adjustment, especially having to pull them off, adjust, and put them back on over and over until I get it right. Besides, in the suspension world, Bilstein is top-notch too.
Having said all of this, my Swifts are 252 lbs/in. I'm thinking I'd like something in the 400 lbs/in range. I've heard good coilovers offer superior ride quality despite stiffer spring rate too, which is an all-around win.
