Suspension & Brakes - How to keep my car going in a straight line

I am done with adding power to my car. For 2007, I need to address handling. Specifically, when I switch to high boost (400 rwhp on my LT1) and I nail it from a stop, the darn rear just goes sideways to the right. Bob at EPP has an excellent writeup on LS1.com about parts to change, which are:
Torque arm
adjustable lower control arms
lower control arm relocation brackets
panhard bar
rear coil spring air bags
I want to add one part at a time and then test it, rather than just buying all the parts and bolting them up at once. What order should I go in? At only 400 rwhp, it seems that a torque arm should not be first. But I am not an expert in this area.
Note - the car is used to go fast in a straight line only; I have no interest in canyon carving. I use my sport bike for that. I also run Nitto DRs on my stock wheels, but I do have 17" wheels from a WS-6 that I can install if required.

adjustable pandard bar will help, itll center the rear so it wont track to one side when your spinning.

i'd start with a Panhard Rod and Rear LCA's To prevent wheel hop and some Sub Frame Connectors so your car doesn't twist like a pretzel when it dead hooks. then go from there. :drive:

Thanks, I thought the rear was off center. I asked the mechanic who installed my stall, and he just said they all do that. Which did not sound correct to me.
I have no wheel hop, you probably need to get traction for that to set in. But I have to settle the sideways first, since I am getting tired of heading for the ditch and having to let off.
Got the SFCs already. Man, what a difference in chassis rigidity.

Keep the steering wheel straight... duhhhh... :D

Keep the steering wheel straight... duhhhh... :DDang, is that the round thing in front of me that keeps me from laying my head down on the dash as I drive? :jest: :jest:

Are you wanting to address handling or straight line performance?

Straight line performance only. I could care less about going around corners fast, I have a sport bike for that.

LCA relocation brackets
Adjustable TQ arm

O.K., I read in EPP's write up how the LCA relocation brackets can help get me traction, which I sorely need.
And I apparently need an adjustable torque arm for traction also (after I stop going sidways, of course). I have been confused by the discussions of them making noise, thumping, etc. Also, it does not seem that I need a relocated one with my low horsepower. Would you agree?