Rear end sag?

[Cadeez]

This weekend I installed some 20mm shims on my front shocks (https://www.ecstuning.com/BMW-E46-330i-M54_3.0L/Suspension/Shocks/Front/ES49751/) which made an absolutely amazing difference. With the Koni/H&R cup kit I've got and the +41 offset of my wheels, my car was almost un-drivable as the front end would heavily rub over every single bump. So once they were installed and I took a few laps around the hood, I measured the ride height side to side to make sure it was even. When doing so, I decided to check the rear height as well and as it turns out, the passenger side rear of my car sags slightly, maybe 3/8" lower than the driver side. I thought it was just on uneven ground, but it wasn't. 3/8" may not seem like much, but to me it's super noticeable with the ride height I have. Couple questions A) what would cause this? And B) any ideas of what I can do to raise it up to match the driver side? Are there shims for the rear springs? Maybe add another upper/lower spring pad?

[fw_fw]

BMW tunes the suspension from the factory with a driver or equivalent weight in the car. Alignment and ride height are thus set assuming that a normal sized person is in the driver's seat, so it would make sense that the passenger side sits a hair lower in an empty car.

[Cadeez]

Hmm, never thought about that, I suppose that could play into it. However the delta still seems a bit more than my body weight evening it out. Guess I could get it and have someone measure it to see. Still won't help the curb side visual when I'm not in the car though :(

[Cadeez]

Below are a variance of different thickness rear spring perch pads, the bulk of which are for the E36 and Z3 platform. I believe only the 5mm and 14.5mm are shown on the parts sites for our cars. Does anyone here know if these will all also fit our E46 platform? They sure look the same in the pics when I google or look them up on parts sites. I'm thinking the 10mm would be the perfect boost my saggy rear end needs

5mm #33 53 1 136 385
7.5mm #33 53 1 136 386
9mm #33 53 1 127 224
10mm #33 53 1 136 387
14.5mm #33 53 1 094 754