As a user of MB Live I have little knowledge of the MB WE (white light), but the error message looks strange. Are you sure that /dev/sda2 and /dev/sda4 have been formatted with ext2/ext3/ext4? tune2fs only supports these 3 filesystems.
I guess that /dev/sda4 is the data partition and /dev/sda1-3 are the system and swap partitions? Because they are relatively small a blocksize of 4096 shouldn't be a problem, but for the data partition things are different. Do you know the blocksize of the data partition on the original disk?
Just to explain briefly what I'm talking about, here are the results of my experiments with blocksize on the data partition of my MB Live. Originally it was set to 65535, which is a good value for optimal performance with large files, but as every file takes at least one block you can easily imagine how much disk space will be wasted when you put a bunch of small files on it. So I reduced the blocksize of the data partition and measured performance. With the standard value of 4096 the partition even refused to mount, with 8192 I succeeded mounting it, but performance was lousy.
Finally I ended up splitting the data partition into 3 partitions, one with ~1TB and two with ~0.5TB. I use the first of the small partitions for data exchange and home directories with many small files, so I started with 8192 again but performance was poor too, so I increased blocksize to 16384 and got reads of about 80MB/s with AFP. The remaining two partitions are for timemachine backups and have a blocksize of 65536.