Thanks to all for helping me sort this out.
New info: Last night the OTHER rear wheel rubbed (so both rears touch on a hard opposite turn).
That makes me think problem is the WIDTH of my new rims (8 as compared to 6.5 stock). They stick out an extra 1.5 inch and catch the top of the arch when the springs are compressed (tires have clear marks). The slight difference in upper gap at the left rear could be normal sag from driver-side weight for 48000 miles (I aint no flyweight).
Ill get Cars & Concepts to check for other problems. If everything is cool I may still have a body shop tap in the lips where they touch.
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’04 m3 coupe • silbergrau/schwartz • 6mt • lux package • xenons • hk • gruppem intake • aa software • uuc rasp-x • borla cat-back • dinan stage 1 suspension • 19" bbs rs-gt • rogue pulleys/ssk/rsms/tranny mounts • cdv removed • home depot clutch stop • euro cross-drilled • stoptech brake lines • vorsteiner cf rear diffuser • cf exterior bits • etc.