Repost with updated info.
Key differences in term of HW/SW specs between DNS-320L and DNS-320:
DNS-320L
Processor: Marvell Kirkwood 88F6702 @1GHz
Memory: 256MB
Kernel: 2.6.31.8
C-Lbrary: 4.3.2
USB port: 1 x 2.0 (rear)
Cooling Fan: AVC DS04010B12U
Power Adapter: 12V, 3A
DNS-320
Processor: Marvell Kirkwood 88F6281 @800Mhz
Memory: 128MB
Kernel: 2.6.22.18
C-library: 4.2.1
USB port: 1 x 2.0 (front)
Cooling Fan: ADDA AD0405HB-G73 (ball bearing type)
Power Adapter: 12V, 4A
Note: Add DNS-320L cooling fan P/N (provided by pizzaking).