[cookiemech]

I've never looked into the exact arrangement of the valve shims (or variable-size buckets) on my Echo, since it's five and a half years old and has 15,000 miles on it (so it's extremely unlikely I'll ever have sufficient mileage to be looking at valve clearances). But I've measured and adjusted (by swapping shims or buckets) clearances on a number of cars and motorcycles, and although it's more pleasant if it just has shims (since you can normally just use a special tool to depress the bucket and then pop the shim out rather than removing the cam), I don't find either to be a terrible job, just time-consuming. Either system holds valve clearance much more reliably than one that uses screw-type adjusters. Currently I maintain two vehicles with around 100,000 miles with shim-type systems (my wife's Sienna and my friend's Tundra) and neither has shown any evidence whatever of drift in the valve clearances. I have not checked clearances on either one, because both start easily, idle well, have good power, good gas mileage, and no abnormal noises from the valvetrain.

I think that valves are pretty much a non-issue for the Yaris. These are tremendously practical cars, and very comfortable for me (6' 1" and a history of lower back problems). My wife really isn't all that interested in cars, and about once a week she exclaims how much she likes hers. She's never done that with any of her other cars.