are these normal things?
 

driving on roads where the surface slants on an angle for rain water to run off the road. does your car pull towards that side? - ie. if it slants down the right side of the road then your car would pull a little to the right .

that wider tires such as the stock svx tires as opposed to something like the honda civic - tend to "follow" the surface more. ie. sometimes it seems like the car is steering itself a little because of little grooves on the road or sometimes if you dont see any dips in the surface at all

that your svx seems like it has a flat tire when you are driving because it really feels like the car is lop-sided? - but it "straightens" out somewhere down the highway

is it possible for the ECUtune stage one to cause some form of a rough idle?

YES to 1 & 2.
YES to 3 if your SVX has been sitting a long time.
Don't know about 4.

:D

I agree with the above post. :)