Yeah everyone has their own opinion. I’ve done both on the ground and on stands. This year it’s going up cause I’m getting my rims poder coated, and have some work to do on it. I mean really it’s not long enough of time to harm the tires. So I would say it’s all what you want to do.
I got mine from Amazon after doing a bunch of research. They’re just as good as any others I researched and were a bunch cheaper. I have had them on the car for a year now. Just make sure you follow the torque specs in directions.
KSP 5X4.5 Wheel Spacers for Mustang, 1 inch 5x114.3mm Tire...
I did 1” on mine all the way around. Just make sure whatever size you go with get hub centric ones. This was mine before and after with the Eibach Sportline springs about 1” lower.