Hello,
Yes, you can buy any DDR2-667 SO-DIMMs and use them, I have two Corsair's that I got for $80 each on NewEgg.com running in my MacBook Pro and it works great, they are even running in dual-channel!
As for replacing the video card, no you cannot. The GPU is soldered to the motherboard, so unless your friend REALLY REALLY REALLY knows what he's doing, there is no way to change the video card.
His reasoning on wanting to change the video card is totally flawed; Parallels doesn't support video acceleration, and even if he did change the video card, it wouldn't change a thing. Parallels emulates everything but the CPU, which technically is virtualized, but it only uses one of the two cores the Core Duo has, and for some reason it shows up as a Celeron. So replacing the video card is not an option, and even if it were, there is no point because Paralles doesn't support video acceleration. Aside from the video acceleration, Parallels can run Vista, you just don't get all the eye candy. But from personal experience, RC1 works perfectly using
Boot Camp. And yes you do get the eye candy that way.
If he wants to use Vista with eye candy, and play DirectX games on his MacBook Pro, the only option he has is to use Boot Camp.
DirectX 10 is not out yet, and anything we could tell you about it would be strictly speculation. I would guess that it would take up to a year or more for Mac's to be getting DirectX 10 video cards. Mac OS X uses OpenGL, and as far as I know a new version for OpenGL isn't due out for a while, at least 6 months after DirectX 10. Because of that, I am doubting that Apple will replace the video cards in their systems with ones that are DirectX 10 compatible, but still OpenGL 2.0, because Mac OS X, again, doesn't use DirectX.
