I contemplate this decision constantly. The base 3.8, doesn't come with sunroof, LSD, Brembos, HIDs, nor extra gadgetry or weight. It's an R-Spec basically, without the LSD, and Brembos, and suspension (which the tracks also have), obviously.
I'm more interested in power, and the 3.8 has it out of the box on a new car. New car warranties are what they are. You hate to have to break the warranty, unless you have to, so bolt-ons only should keep it intact as long as possible, unlike the amount you'd have to put into the 2.0t to get the same power.
Also, so far it's looking like an aftermarket turbo, intercooler, piping, turbo back exhaust, and tuning will be needed on the 2.0t to surpass what the 3.8 stock will do, but you'll also surpass (or about tie) the 3.8 plus bolt-ons and tuning at that point as well. We're talking $4K compared to about $0-2K. So, it's a toss up here. You get more with the 3.8 and goes into financing of the car, or you pull out an extra $4k from your wallet but maybe a bit more power and bragging rights. Toss up.
3.8 for me, so far. But it's close, too close to call really.