Oh sorry kinda skipped that hehe.
You have been answered here
a couple mins ago so you might want to look at that too.
I'll quote here anyway
Originally Posted by riesan
1. the best method is the flash method because you get all the updated baseband and kernel.
2. Just flash the rom to the recent one 2.1.1.A.0.6 baseband 015 because new rom that slade develop uses new baseband and FW 2.1.1.A.0.6
3. non overclock version just a standard with standard CPU on 600mhz and undervolted and overclock version is a CPU overclocked to 710mhz or upper via Cynogemod/Performance/CPU settings and also undervolted.
hope this will answer your question
1. I wouldn't know, I got my 2.1.1.A.0.6 update thru SE.
3. By lack you mean lag? If so I haven't encountered anything like that yet, maybe I haven't pushed my phone to the limit but it's been running really smooth for me on non-overclock version.