The good: The 2012 Acura RDX SH-AWD's turbocharged engine offers good, flat power delivery while its all-wheel-drive system makes this small crossover quite nimble. The Technology package brings the creature comforts we like as well as a great-sounding ELS premium audio rig.The bad: There's advanced driver aid tech available. Fuel economy is merely okay.The bottom line: The 2012 Acura RDX's turbocharged engine delivers good performance, but also causes this pricey crossover to fall flat on its promise of efficiency.In its press materials, Acura calls the 2012 RDX the "right 'right-sized' SUV for today's world." Were I a nitpicker, I could imply that this means the larger Acura MDX is effectively "wrong-sized," but I'm pretty sure that Acura doesn't mean for us to draw such a conclusion.More importantly, I can't help but wonder if Acura means that the RDX is literally "right-sized" as in the crossover's not-too-big,-but-not-too-small stature, or if the automaker was making a larger statement about the vehicle's position in the market. The RDX is priced lower than many of the luxury crossovers in its class (the Audi Q5 or Infiniti EX35, for example) with a smaller engine that makes an attempt at increased efficiency. And when compared with the subpremium brands, the RDX shows a performance and comfort boost over the RAV-4s and CX-7s of the world.Since we've just mentioned the Acura MDX, let's discuss a few of the similarities between the 2012 RDX SH-AWD that recently graced the Car Tech garage and its larger sibling.We'll start in the cabin, specifically at the dashboard. When equipped with Acura's Technology package, the RDX features the same 8-inch display with rearview camera system and Acura Satellite-Linked Navigation System that we've seen in the latest versions of the RDX, TSX, and TL SH-AWD. It features the same voice recognition system and traffic and weather systems with active rerouting and is powered by a similar 10-speaker ELS premium audio system with support for DVD-Audio, Bluetooth hands-free calling and audio streaming, USB and iPod connectivity, and XM Satellite Radio. If you've already read a CNET Acura vehicle review this year, you'll know what to expect here.If you haven't read a CNET Acura review this year, then you should know that the Acura Technology package checks almost all of the right boxes for features that we look for in a tech car. The ELS audio rig sounds fantastic with most audio sources and types of music, the hands-free calling system is clear, and the navigation system (while not the prettiest in this segment) is nothing to complain about.However, the voice command system, while rather comprehensive in its functionality for navigation, requires a bit too much visual attention from the driver. For simple tasks like "Call Fat Jon," it's fine. However, as I started digging into the navigation options, I found that I had to do quite a bit of looking at the screen to know what to say next. It's not what I'd call a cabin-tech dealbreaker, but I found that it was often faster to just pull over and use the dashboard-mounted, knob-based interface instead--which, by the way, is fantastically intuitive.Moving farther back in the cabin, the smaller RDX seats only five passengers in its two rows of seats (as opposed to the MDX's seven-passenger, three-row setup). Although, I wouldn't want to be the poor schmuck stuck in the second row's center position--the RDX has rear hip, shoulder, and legroom on par with the TSX, Acura's smaller sedan. The most important seat in the house, the driver's seat, was comfortable in our Technology-package-equipped example, with eight-way power adjustment and two memory settings.Choosing the smaller RDX over the MDX doesn't just cost you a row of seats and a bit of elbow room. You also lose the ability to spec Acura's Advance and Entertainment package of safety and convenience technology. Adaptive cruise control, the collision-mitigation braking system, blind-spot monitoring, and Acura's active-damper sport suspension are all unavailable on the 2012 RDX, as is the rear-seat entertainment system, but I doubt you'll miss that last bit.