Summer is winding down, but it's still not too late to put the top down and hit the road. For those of us who can't spring for a Corvette or a BMW, here's some good news: Two of the coolest convertibles on the road are also more affordable-- Volkswagen's New Beetle and Chrysler's PT Cruiser. Both start at about $20,000, seat four, and get between 22 and 24 miles per gallon from their four-cylinder engines. Each has fully insulated cloth tops with rear windows made of real glass, which makes them comfort- able to use in winter. Front-wheel drive helps make them safer to drive over snow and ice. Both also offer high- performance turbocharged models starting at about $25,000. Both have bulging fenders and cool, retro personalities. Beyond that, they're very different. The PT Cruiser focuses on practicality, while the Beetle is more fun to drive. That fun comes from the car's chassis, suspension, and overall structure. Crank the steering into a turn and the Car follows like an eager puppy. The engine isn't powerful, but loves to rev, so you can downshift to accelerate. The New Beetle Convertible has developed an unfortunate reputation as a 'chick car' for its cute looks and the lack of power in the standard model. But for an extra $1,600, VW offers its turbocharged version, with a 150 horsepower, 1.8 liter engine, which gives the car some snap. Even so, the convertible top eliminates what little practicality the New Beetle hatchback offers. To fit the folding top, the back seat was narrowed and angled so upright it's uncomfortable. And the folded top sits above a tiny trunk, with only five cubic feet of capacity and accessible through a smaller porthole. Weekend trippers had better not have kids --or plan to rough it with more than a backpack or two. Interior storage is also minuscule. As with the New Beetle hatchback, the windshield is disconcertingly far away, and the wipers clear only a small slit of a view in front. Compared with the profile of the hatchback, however, the convertible sports a top that' s lower and a little less cartoonlike. The PT Cruiser, on the other hand, looks its sinister best with the top up. Peeling the top off reveals its cutesy 'roll hoop'. (Chrysler denies the hoop offers rollover protection and calls it a light bar.) But the Cruiser, like its four-door brethren, offers all the year-round practicality the original Beetle convertible did in its day. The back seat is comfortable for two people, and the trunk is roomy. Unfortunately, it's also hard to access because the big trunk lid gets in the way when open. So instead of standing to load or unload the car, you have to squat or kneel. But the storage space is huge --the biggest I've seen in any convertible. And the back seats fold forward in case you need to carry some long cargo. The interior offers four cup holders and several large storage bins. The 220-horsepower turbocharged engine in the GT model makes the Cruiser seriously quick, which backs up its hot-rod looks. But after that, the driving experience falls apart. Like its hot-rod inspirations, the Cruiser is best on a straight, smooth road. Over bumps, its floppy chassis wobbles like jello. On the highway, the Cruiser I tested needed continual corrections to stay in its lane. The manual shifter on the GT proved sloppy it was hard to be sure which gear the car was about to engage. Several times I hit fifth gear when aiming for third. Chrysler apparently anticipated this problem, as a brief warning chimes to let you know when you're in reverse. Neither the PT Cruiser convertible nor the New Beetle is perfect. But for fun in the sun or even the fall -- what could be better? Both cars brought constant waves, smiles, and stories from passersby. What's a convertible about if it isn't looking good on the road and brightening your day? Those who choose Volkswagen's Ne