street car suspension problems!

Newbie here, hello. Car is a 1995 Formula. Set up for Ozark road trips loaded full of camping gear, driven legally but aggressively on mostly great pavement. Planning to start doing a few autocross events/yr. Here's a rundown of current setup, which I gather is a mishmash of all the wrong parts. Most of this crap, I understand, is designed for straight-line racing and/or impressing techs at tire and muffler shops. Any advice is welcome.

-Stock 16x8 wheels, 245/50/16 BFG G-force SS, 37psi front/32psi rear cold pressure.
-BMR goodies (yeah, I know) - rear control arms (non-adjustable, poly bushings), welded frame connectors, strut tower brace, adjustable panhard rod (poly both ends), stock torque arm.
-Eibach pro-kit springs
-Bilstein HD shocks
-poly motor + trans mounts
-stock sway bars w/ poly end link and clamp bushings.

The car has gained a "bit" of power recently thanks to cam and head work and some old fashioned displacement, and the weaknesses are beginning to show.

Issue #1: The car now squirms around in the rear on hard acceleration, even with no apparent wheelspin. Quite frightening. Difficult to keep it in it's lane even when accelerating from 40-60mph. The rear axle seems to be steering the car.

Issue #2: A recent alignment indicated something funny. Camber and caster were no problem, but with the tie rods adjusted to the limit, toe setting is 1/8" out. No less can be had. Previous alignments presented no problems with setting toe to zero, which I always preferred. Is it possible that the wrong tie rod ends were installed at some point, or is this a function of the lowering springs? How durable are the spindles, and should I suspect them as well after 135k miles?

Question: Should the rear control arms be relocated for the lowered ride height, or is that another Summit catalog myth? Launch traction is definitely reduced now that it sits lower.

Also, the car is under-represented in the braking department. C-5/C-6 brakes or something aftermarket? Don't really want to go larger than 17" wheels.