aftermarket wheels affect TCS/DSC?

its spring time in SLC and i am thinkin about throwin some 19's or maybe 20's (if i can get some to not rub..20's should tuck nicely) on my MS6, and keeping my stock wheels for my winter tires.

..does anyone know if changing the size/weight of the wheel affects the traction control system in anyway??? i kinda figure it would have to affect it, but maybe not. i know that it affects performance, i.e. acceleration, but is it going to affect a safety feature like some sort of brake assistance in the TCS or DSC ?

also i've heard that changing the rims turns on the tire pressure monitoring system light..is this true? does anyone know any fixes for this ?

any info would be great, thanks ;-p

Personally I don't have the tire pressure monitoring...so no issue their, but the only problem I could imagine is that if the wheels weighed more than the stock ones they might affect braking action minimally, but I highly doubt anyone would notice it since it's not like your TCS or DSC are coming on so much that you would notice it immediately.
Those systems just detect wheel slip and wheel changes would not affect that.

I wasn't even aware that tire pressure monitoring was an option on the Mazdaspeed6.

Different size tires require different pressures so you may end up running a tire pressure that sets off the warning all the time.

As far as ABS and DSC go, as long as you keep the outside diameter of the tire within 3% of the original tire/wheel combo you shouldn't have any problems. Weight of the wheel will affect performance but shouldn't cause any problems with the electrical components.