WiseguyZ28

Last month i got two nails in two different tires leaving one unrepairable. I'm gettin new rims after winter as well as new tires. But for now, i didn't wanna get new tires that only need to last this winter at least. So my bro had 2 stock 235/55 tires from his firebird. I got those two put on today and they put the 235/55 tires in the back, i think they just didn't wanna take off all 4 tires so decided to take off the one that needed to be changed and the opposite side.

Wouldn't fatter tires be better in the rear? or should i just leave it as it is?