What's the downside of not replacing the struts (i.e., front suspension) on a Previa that's 15 yrs old, but otherwise fantaastic?

The down-side. Well, the down-side of not replacing your Struts and/or your rear shocks, is just a little bit more of a bumpy non-responsive ride, but insofar as the long term problem that I feel is expensive, is that with bad shocks or struts, your tires will begin "cupping." They will have cup marks all along the tread and eventually (the tires) will have to be replaced...again and again. I know you said the front struts are bad, but the rear shocks usually go first and this can be checked by standing on the rear bumper and jumping up & down on the rear end. If the rear end bounces more than once when you stop jumping they also need replacing. That's the downside of not replacing shocks or struts. Back in the late 1980's I had a Dodge Monaco that had bad front shocks, and cupped out my tires badly. When I was replacing the shocks, one was so bad that the oil in it sprayed all over my toolbox and a friend of mine. Not cool, but I was working at a Chrysler Store A(Dealership) and it was expected.

If you can afford tires, then let the struts go, if not, then wait for a sale on Monroe® shocks and struts and replace all of them at the same time. It will be well worth it.

~Stillin~ (IMG:style_emoticons/default/s12.gif)

"Still Living on the Right Side of Dirt..." (IMG:style_emoticons/default/harhar.gif)