I have a 2008 G37s 6MT with the stock suspension, stock wheels with 275/35R19 tires on the rear for the summer and 18x8 +40 wheels w/ 225/50R18 tires for the winter.

The last alignment I had done showed everything in spec both before and after. It was done with the above mentioned winter setup. This was done a few seasons ago. My car handles predictably, tracks straight and stays planted in dry conditions. I haven't thought to get an alignment as a result.

What I am seeing is that my rear summer tires (Bridgestone RE050a) look worn more on the outside edge. The outermost grove looks very shallow.
1. Is the outermost groove a full depth groove? (I think it isn't)
2. Would the wheel and tire setup used on the car affect alignment when different wheels are put on the car?
....2a. If the answer to the above is yes/depends on the setup, would it apply to my setup?
....2b. Would getting an alignment now prevent further uneven wear or will I need to replace these tires? They the inner three grooves are not close to the wear bars, probably ~5/32" or 6/32".
....2c. Would an alignment every season/swap be necessary? (I am buying new winter tires this fall, would hate for them to wear unevenly).

 

Bumpity Bump Bump

 

Shoot a PM to TVPostSound he's the alignment guru on the site and should be able to shed some light. Different wheels/tires may affect alignment if the old tires are have improper wear and the other tires are new, and if your alignment stays true you shouldn't need to do it every season. As far as the outer tread wear issues you're going through TVPost should be able to help.
G/L and post back if you get some closure w/ this.
Brad