You will not be able to adjust for camber with this setup. So when you lower an IRS car you naturally get negative camber. With wider and negative offset wheels its helps tuck them into the wheel wells. Its not the best for driving geometry and most do not like the look of the angled wheels. So to correct the camber back to the stock near zero degrees people install Byrons Brackets, they slot their rear crossmember, or they buy an adjustable rear crossmember.
Because the wheels are going to be so close to the fender (ever with a roll) you will need the negative camber so the tires dont rub. Theres no way for you to correct the camber back to the proper alignment.
What does that mean to you? Well, you will have to deal with inward angled wheels. You wont have the proper IRS geometry. Some tire/mechanics will not touch a lowered car for alignments if they can not adjust rear camber. Places wont put their name on a job where the wheels are negative like that because they feel its unsafe.
If you can live with all that, then youre good to go. 15x7 +0 will physically fit on the car.