HDD controller config

[DL126]

Hey guys.
I'm building a fairly high end workstation for a customer.
I have a question about the HDD controller config.
We want as much speed & efficiency from this system as possible.

MOBO = Intel DX58SO
CPU = i7 920
12 Gig RAM
HDD's = 1 Intel X25M 160Gig & 2 WD 300Gig Velociraptors
Optical = 2 DVDRW's
OS = Win 7 x64

Currently, I have the onboard ICH10R set to RAID in BIOS
ALL drives hooked to this controller.
The Intel drive is for Win7 & all programs.
The WD drives are set to RAID 1. (This is where his data will be stored.)

Am I losing speed by having the SSD hooked to a controller that is in RAID mode?
What about trim? Is that being passed to the SSD?

I'm wondering if I need to add a SATA RAID controller card for the data drives & then set the ICH10R back to AHCI and start over.
Your input please.

TIA