The 4th gen LS1 F-bodies are legendary and timeless. The reason being:
they are fast, good looking, EASY to mod/work on, and best of all.. inexpensive.
If you're set on a T/A and you want to mod it heavily, don't even bother looking for a WS6 as you will pay thru the nose.
Differences between WS6 and standard T/A:
WS6 has "upgraded" (aka slightly better than crap) shocks
WS6 has a meaner hood
WS6 automatic cars have a 3.23 rear end whereas a standard T/A has 2.73
WS6 cars came stock with wider 17" wheels, T/A came with 16s
If all that sounds like stuff you would be replacing anyway (or if you're looking for a 6 speed) then don't bother with a WS6 as they are very sought after and you will likely be paying a lot no matter what the mileage. Now a Firehawk on the other hand..
is a good way to start, preferably an 02'. Comes stock with an SLP Lid, SLP catback, and most came with very good Bilstein shocks in addition to everything else the WS6 has. You WILL be paying through the nose for one of these, but there is also the collector's value to factor in.