Whenever I test drive a car, I pay close attention to the seats. Do they properly support my back? Is the seat too hard or too soft? Does it have a comfortable shape? And, most of all, how well does it restrain my torso when I hustle the car through some quick curves?

No other part of the car is as likely to disppoint. Many seats are too small, even for someone my modest size. A number are too soft, while some are too hard. And very, very few provide sufficient lateral support in hard turns.

It’s easy to see why seats aren’t better: people come in many different shapes and sizes, and have different tastes. The result of an attempt to create a single seat for everyone is bound to end up perfect for few.

This is especially the case with a seat’s side bolsters. Make them too large and firm, and some people will find the seat too difficult to get into and out of. Space the bolsters to fit someone my size, and people with broad backs will find them excruciating. I once owned a 1996 Ford Contour SE. Its seats had large, firm, tightly spaced bolsters. I loved them. Most others who sat in the car hated them. The following model year Ford greatly reduced the size of the bolsters. To avoid this problem, even sizable bolsters are usually too widely spaced to do me much good.

Luckily, there is a solution: adjustable side bolsters. While I often like tightly spaced bolsters, sometimes I want them more than other times. When driving the current BMW 3-Series with Sport Package, for example, I’ll tighten them up for twisty roads, then spread them wide for highway driving. So even someone with my taste in seats will find adjustable bolsters very useful.

Only one problem: they’re offered in only a handful of vehicles: a few BMW models, a few Mercedes models, the Chervolet Corvette, and the redesigned Infiniti G35 are all I can recall. I’m not alone in appreciating this feature, and would gladly pay the couple hundred bucks it typically adds to a car’s price.

So, why are adjustable side bolsters so rare? I haven’t a clue.