Look, forget your friend for a minute. You want to overclock your computer and want to buy new RAM and CPU. How long do you think that expense will last you before you decide to over over clock!
When you initially buy something know what's the limit. Maybe next year at this time what we have now will be slowwwwwwwww. Instead of spending, just be patience and wait till the prices go down and buy a mobo, cpu and RAM that have potential. Never put too much on old equipment.
I'd wait for the right occassion; you shouldn't be in need of speed that much. OC will only give you so much which is not always wise if you didn't initially purchase your system with the idea of OC.
And for the cas latency of a RAM, the lower the figure, the faster it is.
Asus P4P800 SE
Intel P4 3.2 Gig 1024 Meg PC3200 cas latency 2.5
RAID 0 2-36.7 Gig SATA WD 10,000 RPM
200 Gig WD ATI ALL-IN-WONDER 9600XT
6500 Kb bandwith Internet Connection