Any time you put the suspension apart you need to do a alignment. Before you add the toe-links make sure you add boots to them to protect the heim joints from dirt/dust & do not grease or oil them up. Then the tech will adjust your camber & then the toe on the rear first & then adjust the toe on the front after doing the rear, w/ getting the s/w straight. As far as the rear height & the spring perchs all the way down, the only thing left is to run shorter springs. I've seen where the springs perchs are set a few inches from the bottom & the car was sitting pretty low. Be interested in where he figured the height of the perches compared to the stock arms. Did you get a chance to compare his arms & the stock ones side by side? Just looking in pix the stock arms have pretty low spring pockets.
Introduce Mr. Torsen to the mix
Bigger brakes then you- D23 crew- D-Tech- Sedan Revolution= #131