The RX 350 is Lexus' most important car, and it's not hard to see why

The Lexus RX has been around for so long that it's easy to forget how significant a vehicle it was when it hit the scene way back in 1998.

Up to that point, SUVs had essentially been upscale trucks. Lexus' parent company, Toyota, realized that many people, especially in America, were buying rugged four-wheel-drive SUVs when all they really wanted was SUV scale and utility. Their SUVs never got a whiff of trail; the closest they came to off-roading was when the parking lot of the Short Hills Mall needed a repaving.

Enter the RX, the first in a new breed of "crossover" SUVs, built not on truck platforms, but on more car-like undergirdings.

The RX was an immediate hit and has remained so for decades. Lexus has sold over 2 million of the RX 350, making it by far the most important vehicle in the luxury brand's portfolio. This is not a car that Lexus can afford to screw up.

That said, Lexus did revamp the RX, rolling out the new crossover at the New York Auto Show last year. The fourth-generation crossover is just as versatile as it's always been, but the design is newly aggressive, notably up front.

I live in the suburbs of New Jersey. This is the heart of the heart of RX country. Lexus loaned us a $60,000 RX 350 F Sport version, with all-wheel drive, and we tooled around in it around for a week. (A front-wheel-drive RX 350 is available, as is a hybrid RX 450.) Here's the lowdown: