Just another suggestion, since you need a wagon, why not consider the 6 wagon with the V6 in it? They're giving crazy rebates on those as well.
As for the engine stuff, I think that 4 years ago, most people didn't even think of Mazda as being worthwhile in terms of aftermarket. Since the inception of the 2.3 MZR, tons of companies have started making products for them. With Ford going to the EcoBoost line in the next 5 years, the DISI/turbo engines should take off even more, since Ford will probably utilize a detuned version of this engine in some vehicle at a later date.
Audi's are great engines, and since they're used in the VW lines as well, gives the aftermarket companies a good opportunity to make a product that applies to multiple vehicles. I think we'll see that from Mazda/Ford as well.