Go to your local home center and buy a couple bags of concrete mix or play sand, then add them to your trunk one at a time until the back end starts to sag. Total up the weight minus one or two bags and you know how much you can reasonably carry. You'll probably run out of space (volume) long before you exceed the weight limit. Oh, you can then use the play sand for a sand box or the cement to anchor the swing set for the little one. <img src="images/graemlins/smirk.gif" alt="" />

Brian