So I installed the Lenovo drivers by running the install, going to my intel ICH Storage Controller in Device Manager and "updating drivers". It asked me to reboot and now it says i am on version 188.8.131.522.
My configuration is:
Dell Studio XPS 9000 (435t)
Onboard Intel ICH10R
80 gig SSD as OS drive (on board)
2*500gig 7200 drives in RAID 0 (onboard)
BIOS set to RAID (as opposed to achi)
Here are my answers:
I've tried the RST driver and it made my system drastically slower. I went back to msahci.
Other users made other experiences. They reported to have gotten a performance increase after having installed the Intel drivers.
Conclusion: Each system may react differently. The user has to find out him/herself, which is the best solution.