Thanks everyone! I just took the June2007 exam as my cold diagnostic. I think i will start off with the LSAT Trainer book and 7sage and then move on from there :)
Probably the main difference between "new" and "old" is the addition of comparative passages in RC. The free June2007 is the beginning of such change. So anything PT's starting with Pt 52 (in addition to June2007) has the comparative reading.
They are pretty ok... should be used as a last resort though... so I would suggest saving them till may/ June... the first one you would have done... its basically June2007 all over again with Indian names... the others I think are different.
@JuliaZLSAT PT52 is September 2007, June2007 is the free PT that LSAT provides so I think they just skipped it in the numbering (or it's listed in some places as 51.5).