NO, that is a very radical change and may rub steering tires on the frame.
Swap rear tires from right to left, see if the wobble changes sides. If the wobble changed sides you have a bent rim or a bad tire. If the wobble didn't change sides you have a bent axle or hub.
The short answer is yes.
what tires can I use for my 2005 Subaru Outback 2.5i Wagon?
best tires for Subaru outback 2008
The rear tires except Subaru which does the front.
Subaru Outback
Yes. Not only can, but should be.
See "Tires" on page 5 of chapter 12 "Specifications" in the "OWNER'S MANUAL"...
Fragmented question?? If you have under 3/32nd's remaining on your tires replace them. If you have wires hanging out of your tires replace them. Replace tires as needed or rather replace all at once if you do not like mis-matched tires. However many people will replace just two tires at a time then rotate when the other two need replacement.
I have found that Sam's Club and Costco have the lowest prices on new tires. They also will replace the tires for you right at both stores. I have found them to be very quick as well.
They can but changing tire size will change speedometer readings and the way your car handles. You also must have all four the same size. There is a link to a tire size calculator in related links.
It could be your tires, have them checked.