So I installed my bc coilovers and set my ride hieght. Everything was fine. Gave it a week for springs to settle, then went an inch lower all the way around. Now I have a shake when I accelerate I have had it aligned best it could be without camber arms and stuff. What could it be? Tire balance? Axel?

Did you get it aligned before or after you dropped it another inch? How long has the car been lowered and has it gotten progressively worse or just after you decided to go another inch lower? We need more details.

I got in aligned before and after both time I lowered it, I got a lifetime alignment through Firestone.

I have BC's and haven't experienced these symptoms and I've adjusted ride height many times (always aligned right after with my camber kit). Only time I've ever had vibration was on my TSX and it was due to a bad axle. Only happened to me at freeway speeds. Replaced both axles for peace of mind and it was gone. My TSX had BC's as well.

How many miles are on your TL?

Shake at all higher speeds = Tires out of balance, need to rebalance. Check bushings
Shake during Acceleration only = Axles or joints are bad, check and replace
Shake during Braking = Brake rotors need to be resurfaced/replaced.

As csmeance mentioned, sounds like it's something else going on with the car not necessarily alignment related. Lowering the car may have stressed one of the axles and now you may need a new one. It's impossible to tell without taking a look at the car, but sounds to me like there's something mechanically wrong.