You made the right decision.
We don't have snow here. I don't have to drive in all weather conditions.
Only dry roads for my Bonne.

So, what size can we fit on the stock rim? i want to go as wide as possible when my tires wear out but not any taller. can we get the 265 50'* on there?

Remember Mark, that you have decreased the overall diameter of your tire by going to a 245/45 R 17 tire.

Xac - the 255/50 R 17 tire is the same overall diameter as the stock 235/55 R 17 tire.
It is as large/wide as you can go without rubbing.
Mine clear everything by the width of my baby finger at every extreme.

I did not notice any difference in my gas mileage with the Michelin Pilots? I run mine at 32lbs. In any case, I was so glad to get rid of the RSA'*, I would accept less gas mileage to have a smooth ride - my RSA'* could not be balanced and I will never understand why GM puts these tires on their premium brands.

...because they are cheap and GM tries to make as much $$ as they can.
Why do you think they stayed with FWD and the trani'* are built/sold with such a low torque/reliability rating.
They do score an A rating for style. IMO

BTW, this is certainly not their premium vehicle. Have you priced any of their trucks or SUV'* lately?

We drive luxury family cars.....that have a little attitude. Most of us improve the attitude part.

What do you mean by "low torque/reliability rating?

i know one of you can give me a link explaining all the spec of these tires . . . what speed rating is better, what wear number is better, etc.

how about 255/50WR17 BFGoodrich g-Force T/A KDWS Blackwall ?

Meaning that they are built with the max reliable torque rating of the transmission being so close to that of which the engine is already putting out. Mod a bit and hammer on it and you are sure to have transmission troubles. Atleast these trannies are easy to rebuild stronger than original. Try doing that with a 42LE mopar tranny found in the Intrepid, 300M, Concorde, Vision... Compared to the 42LE, the tranny in the bonnevilles can take a real beating, and if you have problems, you can always find the beefed up parts to put back in.

Back to the subject of tires. I just put on a set of Dunlop SP Winter Sport M3 winter tires on my bonnie. These things are amazing. They whine alittle in the rain, but man, their performance is better than my RSA'*. The RSA'* have been very good to me and are proving to last quite awhile (now at 34k miles). I have had no issues with the tires, but I was amazed at how well the car handled with the snows on it in the wet and dry. Not to mention how sure-footed the car is in the snow with these puppies on it. My experience with snow tires has always been exactly the opposite as what I have experienced with these. On my old car ('94 Intrepid), it handled much more loose with the snow tires on (due to the lack of stiffness in the sidewall on the snows). Those snow tires were just from a local tire shop and I don't even remember what they were. I think that these Dunlop M3'* are built much more solid than my previous snows.

Here'* the specs on my snow tires:
Dunlop SP Winter Sport M3 from Tirerack.com
And here'* a shot of them on the car: