After researching the opinions on this board it seems that the sport package, when included with an 'xi' model, does not incorporate the "sport tuned suspension."

I've read that H&R makes springs for the 328xi coupe and was wondering what the opinions were on this forum regarding the safety of using a set of springs like this with BMW's all-wheel-drive system.

As other spring manufacturer's specifically note that the 328i coupe springs are incompatible with the 328xi coupe, I'm assuming that H&R made these springs specifically for the xi, perhaps using a slightly higher spring rate to handle the extra weight?

I'm worried more about additional wear and tear on the all-wheel-drive system or anything else I may be unaware of. Opinions?

There should be no worries, as long as you don't drop it too far. The point of their AWD system is for weather and not performance so lowering it isn't the best idea for snow (since you get less clearance).

I don't know if this is true with all german cars, but VWs come about an inch higher here in the US than the rest of the world because of our bumper height standards. So assuming that is the same for BMW, lowering it should put it back to where it was designed to be.