On the LSD:
Very quick 60' times are there with stock HD diffs.
http://www.3800pro.com/forum/fwdlaunches.php
So why use a clutch based diff that will add more clutch material to your trans system if the place where you'd notice the biggest difference would be the autocross or road course?
To the OP of this thread: If you have to ask, you probably won't do it. Pretty much the standard with this platform. Anything worth doing is more worthwhile doing in a different platform.
To ls1camino: To claim that the blower isn't a restriction is rather interesting.
The rotors were not designed to move compressed air, many different paths of logic would suggest many different things. Until we see some test results of the blower on a blower test rig, claiming one thing or another is kinda pointless.
Dyno results or track slips do not count as evidence to support claims such as "the blower is not a restriction".
To claim you'd destroy other cars with similar internal mods is also an interesting claim.
A stall is not an internal engine mod thus the larger turbo car could have a larger stall and thus spool the larger turbo and theoretically have similar torque/power available to it throughout the run.
Tires will not solve the inherit issues with launching a W body. Chassis has numerous flaws such as the weak LCA design and FWD layout. Plenty of time can be shaved off of your ET by focusing on suspension, even if the car is otherwise stock.