I installer Garhauer's "E-Z Glide" adjustable genoa car system on our Ericson 33. As noted in previous posts, these cars roll on itty bitty ball bearings on your existing tee track, and actually work quite well. The Harken ststem is generally considered to be better, but replacing the track is a major hassle and a considerable expense. Ya pays yer money and makes yer choice!
Interesting foctoid: There are three or four "standard" sizes of Tee track. The thickness of the Tee varies with manufacturer and/or model. If you order a set of Garhauer E-Z Glide cars, please make very carful and precise measurement of the track Tee thickness! A measuring tape won't do it - you will probably need a precision caliper or similar measuring device. I found out the hard way that the Garhaur E-Z Glide cars are high precision units built for each specific "stardard" size of Tee track. A Garhaur catalog is a very nice thing to have in your boat library. They make very nice "boat jewlery" at affordable prices. I've replaced most of the various turning blocks on our E-33 with Garhaur blocks.
I would argue that remotely adjustable genoa cars are more useful and appropriate on a "cruising" boat than on a "racing" boat. Think about it - you race with a full crrew and having a crew member adjust the car when on the opposite tack in no big deal. When cruising, you typically have a much smaller crew - as few as single handed! Also, remotely adjustable cars are a perfect match to the roller furling/reefing headsails that we all have (or plan to have). The wind is up, you roll in some headsail by pulling a string, then move the genoa cars forward by pulling another string - all from the safety and comfort of the cockpit.
I have rigged my "pull backs" with bungee cord. One less string to deal with. The down side is that the bungees only last a couple of seasons, but bungee cord is "relatively" cheap. If there is sufficient interest, I might be persuaded to snap a few pics of my installation.
Mike O.
E-33 JP Foolish