considering that run flats cost substantially more, i was initially hesitant about swapping out my rims and re-using the stock runflats, i still am after. my thoughts and observations.

1) stock rims weigh in at more than 10kg each, forged, 6.9kg.

2) original rims have a different rolled profile to prevent bead slippage.

3) tire pressure monitoring system is in e hub, not the rim.

4) runflats not designed to work on regular rims. once deflated, it's substantially easier for bead to slip off during hard cornering.

5) the weight of the runflats is not that much heavier. it's is, but not substantial.

i'm posting cuz had i known (4), i would have re-considered.

 

But you shouldn't be doing hard cornering with deflated tires. The runflats are to get you to somewhere to have the leak fixed or the tire replaced.
I was running run-flats on non-OEM rims for about a year. When my flat tire indicator came on, I slowed down immediately to about 45, finished my errand carefully and with no hard cornering, then got new tires ASAP (they were worn out).