I also found the K member and A arms change is good for 50lbs
Front seats are heavy pigs as well, change to CR1s is another 50lbs.
Shaker 1000 amps and sub is about 50lbs.
Rear seat is pretty light, maybe 10lb total
On the dyno, I will use my 3 peice G7s, they weigh 42lbs, so over stock 45lbs, that is about 96lbs (12lbs)in sprung weight.
Carbon Drive shaft is another 96lbs in sprung weight (12lbs).
Jack and spare 50lbs
So, if I dump another grand I can drop about 234lbs. sprung a little more.
That would be good for almost .4 of a sec in the quarter.