Memory Recommendations - With Little Options!!!

Hey Guys...

I am using a Giga-byte GA-8SQ800 (Sis 655 chipset) mobo that support DDR400 in Dual Channel. Right now, I have 4 sticks of 256MB Crucial DDR333 (PC2700). In Giga-Byte's documentation, they RECOMMEND(???) the following DDR400 to be used with this mobo:

Micron (MT16VDDT3264AG-403B2)
Corsair XMS (CMX256A-3200 XMS3202v1.1 024458)
Kingmax (MPXB62D-68KX3)
Kingston Value (KVR400X64C25/512)

Now, I know that Crucial is made by Micron, but wanted to pose the following questions to yall for input:

1 - Would an upgrade from PC2700 dual channel to PC3200 dual channel be a visible gain in performance? (i.e - is it worth it?)
2 - If so, would I lean to follow the mobo's manufacturer's "recommendation"?
3 - If I follow the manufacturer's recommendation on the above types, which memory would you recommend? I do not overclock, so what I am looknig for is best performance.

The one final caveat is that upgrading the mobo is not an option at this point.

Thanks!

I would say that the Corsair is your best choice out of those 4. Plus if you do decide to overclock, several people have had great oc's with that memory at tight timings (5-2-2-2)