I think if you check the specifications of both tires diameters there is only about 3/8" difference.

I don't remember if it's overall diameter or the side wall of the rim. That's what it will raise the axle up.

The R number or aspect ratio changes between the two. The lower R times the width compensates out any great difference.

I have 205's all the way around on my sedan and have used them on my wagon when I used to carry heavy loads. The weight capacity increases slightly.

Yes the ride is slightly softer because you have a little larger oval under the the rim.
If really overload the back end, it is possible to rub the inner fender on the rear of the car during cornering. I had noticed this on my wagon with 205's before I added IPD overload springs.

I suggest that you look into XRAYBOB's post about using Hockey Pucks for raising the rear. I thought it was a inexpensive answer to his problem which might be the same as yours, especially if your springs have sagged a tiny bit.

The shorter the side wall gives a harder ride but if you like quicker steering response.
They call it feeling the road nowadays!
You might like to go to bigger fancy rims, that you see before the car and with those rubber bands for tires! Your stance will not change much again, because you need clearance for wheels.

If you get that paint job, you spoke about doing and add some Hockey Pucks, you might gain those fans as well!!
(:-)
Phil