That hasn't been my experience however...
Qwik95SC: If I had to do it again, I'd actually go with the 245/50/17 Tires.
I've got the 17x9" Rims and the 255/50/17 and I've run into rubbing on the rear fenders when going over high speed dips as well as a very nasty front rub that actually "chunked" the tire when I took a dip in the road at 30 MPH.
In fact the front rubbing was so bad that it pulled the lip down a little bit, I had to roll it a little bit to get it back up.
I got the rear fenders trimmed (Rolling WON'T work right because there is way too much fender gap) AND I am running -1.5º rear camber to compensate too.
So basically, there isn't rubbing in the back anymore, and I don't take any dips in the road at anything over 20mph.
With the 16" tires I didn't have these issues.
If you are asking about Turning and Steering angles, the Tires and wheels WON'T rub. I haven't had an issue there.
My suspension is stock and I am NOT lowered. Sometimes the actual width of the tire will vary from manufacturer to manufacturer. The tires that I have been running are BFGoodrich G-Force KDWS tires.
My Rims are the 03' Cobra style and I think they are a 36mm offset, I can't remember.
Up front the inside top lip of the rim comes about 1/4" to the front spindle. I'm sure a little more "meat" could be shaved off of the pedistal of the wheel but then I'd be running dangerously close to the spindle. Maybe the spindle would need to be ground out a little bit too. Oh and the bottom part of my upper ball joints needed to be ground off to prevent rubbing too. But that wasn't such a big deal.
I'm really starting to think that the rest of the SCCOA'ers who run 245's up front do so for these reasons. Out back you can go hog wild and that's why alot of guys will run 275series in the back and staggered up front. I wanted to keep the tire rotation that's why I went with consistant sizes all around. You'll also notice more that the front track of the car is wider than the rear, hence the reason why the front tires bulge out a bit more. Kinda makes it look like a front wheel drive drag ricer errr... Racer.
I'm also pretty sure that you can easily fit 245 series tires over a 9" rim without any issues.
ALso another reason why some guys run the 245/45/17 tires is because the tires are overall 1" shorter, it gives natural lowering to the car. And they compensate with a different speedo gear.
Oh and last but not least.... that smooth creamy cadillac ride you've come to love from these cars and was probably one of the reasons why you got it in the first place? Forget it. It'll ride like a nasty F-150 with the 17x9's, 255's and 35psi cold pressure. Garunteed.
It will however take off-ramps at 70mph without batting an eye and will probably be the BIGGEST increase you'd get from any suspension modification out there.
So the choice is yours. Just thought I'd let you know the ups (and mostly downs) of my experience thusfar.