Does anyone else have this problem? IS300 on stock height but has bad tire wear on the inside, especially on the rear tires... suggestions?

no one huh my shiiit must be F'ed up then eh

how old are your tires?
and after time your car will un-align itself. it happened to me with my fronts when i was at stock height.

there pretty old now, i just flipped the tires so i could get some more life out of em, now they are al bald as **** on the outside

I have the same problem..

The 1IS have a stock setting to have a little negative camber. Go to a good alignment shop and have them zero out the camber a little and toe it in a little more as well. That should fix your alignment issues.

I have slight inner wear too and will be hopefully aligning and flipping them next month pending my finances.

yea, that is stock camber. it also helps increases our turn radius in the front, if you want to save tread you should try to avoid making sharp turns and u-turns.