Please note that if you have questions regarding the Windows Experience Index I suggest you to contact the operating system manufacturer since this is part of the (Os)
Regarding the IDE Vs. AHCI question, I suggest you to use the AHCI option, since the TRIM command will be supported natively only if you select the AHCI prior of the installation of the (Os), it is recommended to keep the AHCI option
If you want you can update the sata drivers but the most important update is the firmware update of the ssd.
Thank you. I enabled AHCI after install and updated the SATA drivers as well as installed the Intel Rapid Storage file. Rechecking the windows experience saw it move back up to 7.7 for the SSD !