“My question is all SATA II Drives backwards compatible or am I going to encounter problems.”
Each SATA standard is backwards compatible with the previous one.
SATA 1 transfer speed 1.5Gbit/s speed - about 150MB/sec
SATA 2 doubled the speed to 3Gbit/s - about 300MB/sec
SATA 3 ® transfer speed 6GBit/s - about 600MB/sec. and will be available around 2011.
SATA 4 may also be just visible on the horizon 12Gbit/s – about 1200MB/sec