Wouldn't the drop in read/write speed be cause for concern?
A lower write speed will generally mean a better quality write, I don't write at anything above 6x - not unless I don't want a disc to be read on the majority of playback devices.
Q: Aren't all drives manufactured after 2000 or 2001 RPC2? I thought I read that somewhere. Or did that just apply to drives sold in the USA?
Yes, all drives
should be RPC2, (part of the DVD Alliance/Forum, **AA, MPEG-LA entanglement), but you can still flash them back to RPC1 to get around region encoding, (well, TBH, I haven't seen a recent factory drive that wasn't RPC2, eg. LiteOn, Samsung, Pioneer, Optiarc, Benq or LG, but I guess that doesn't mean they don't exist).
From memory the basic difference between them was the way the region was requested/reported.
DVD: "Hi, I'm region 4."
Drive: "OK, I can play you."
DVD: "Hi, what region are you?"
Drive: "I'm region 0, (ie. free)."
Drive: "Hello? Are you still there?"
Flashing the drive to RPC1 allowed you to make it region free. RPC2 put the onus on the DVD software/encoding to check whether the drive was of the correct region which, at the time, was harder to bypass. If the drive reports itself as RPC1 then it falls back to the old way of doing things which allowed for region free.
These days you can rip a DVD removing the region encoding in the process which kind of makes the whole region thing moot unless, of course, you are an honest, law-abiding person....in which case you're screwed.
For drive info, if you use ImgBurn you can go to the Tools->Drive menu to check capabilities/region/etc.