I have used Poly bushings on a BMW for upper and lower control arms. Poly bushings are a royal PITA due to the noise they make. You need to grease them routinely or your car will make an insane racket within a few months.
For standard street use, just use stock and forget even thinking Poly.
If you're just looking for straight handling, no expenses spared then you could always ask Tripoint about their multilink front suspension setup that they were using on their 6. I believe that you were actually able to purchase the setup at one point.
The hassle factor of dealing with Poly, assuming you don't need them for some racing setup, just isn't worth it. The OEM may not last, but replacing them every 70k or whatever isn't exactly the same as loading your car on a lift and trying to figure out how to get grease into poly (may have to remove, or drill something to get grease into them).
If you check the size of the bushings, bet you can find something similar out there that will fit for less. The BMW Poly bushings were damn cheap.
After dealing with a BMW, control arms will always be OEM on just about any car I have. Just not worth the hassle if you buy something aftermarket and then have to deal with suspension issues.
Supercharger money that's why, just a real setback but 751.00 really is a lot of dough ill send my old ones to energy suspension so they could get this kit assembled because this kit should have been developed by now and also should be cheaper by 250 at least