SATA Questions

In preparation to building myself a new PC, I've been playing with setting up a RAID system on my current box. After a week's time and many screw ups including loosing about 300+GB of stored data, I've finally got a setup I think I like. I have set up 2X 300GB SATA & 2X 1TB SATA HDDs on the ICH6R with the Intel Matrix Storage Manager so that:

The 2X300GB's are 2 drives: C:\ = 50GB RAID0 with the balance as D:\ = ~275GB RAID1.
They show up as actual separate drives in the partition utility.

The 2X 1TB's are partitioned into E:\ = 500GB RAID1 and F:\ = 500GB RAID1.
They show as partitions on a single drive.

All partitions are redundant except for C:\. C:\ is backed up with an image stored on one of the other patrtiutions on the other HDD pair.

I also OC'd the CPU by 10%. I've noted a marked improvement in C:\'s performance. Undoubtedly due to both the RAID0 and the OCing.

So my questions:
1. With both C:\RAID0 & D:\RAID1 on the same HDD pair, I assume that data transfer between them will be slower than between C:\ and the partitions on the other HDD pair. Correct?

2. While I haven't been able to get it set up and running yet, I'm wondering if AHCI would give better performance than RAID with the SATA drives and their NCQ capability. ???

3. My MoBo also has a SI3114 controler with 4 SATA connections. Would there be any advantage to using that compare to the ICH6R set up?

4. In my proposed new box, I want to use 2ea. SATA DVD-RWs. The newer ICH10R seems to support 6 SATA connections. If I leave 2 connections as non RAID, they should be OK for the optical drives. Correct?

5. My old stand by, Partition Magic, seemed to be not very good at working with the RAID setups. After looking around here a bit, I decided to give Easeus Partition Manager a try. The Server Edition's boot disc says that it doesn't work with RAID. Is there a better partition manager for handling RAID setups?

6. And finally, In my playing with getting the RAID setup up and running, I moved a lot of data around from partition to partition trying to keep it safe while setting up RAID pairs. Copy and pasting hundreds of GBs of files from one partition to another seemed to break partition tables. Not just once but several times. That's how I lost the 300+GB of data. Is there a better way to move large quantities of data from partition to partition?

Any advice on any of this will be deeply appreciated.
Thx