are your wheels like this / \
looking from the back (negative camber),
or from the top of the car (toe in)?
check your rear trailing arm bushings. make sure they aren't cracked, and that they don't have any flex in them. I would personally recommend the Mugen hard rubber rear trailing arm bushings, especially if you plan to lower the car from stock height. Also, strut braces and tie bars will help to stiffen the body with the greater spring rates associated with lowering the car. The bushings are about $100-$120 or so, and whatever a machine shop would charge you to press the old ones out, and the new ones in... you will not be able to wrench them in. The Neuspeed braces I have were like $90 for the upper rear strut tower brace, and like $70 for the rear lower tie bar. Combined with some tight (450 to 600 lb) springs, double-valved & adjustable struts, and those Mugen hard bushings, it's a whole new car. That's just my $0.02.
For tracking the thread, down near the bottom right of this table, directly above "add reply" is track this topic. May be in a different place depending on your browser. You can always search the page for it using search, as it is actually a text link. Hope that helps.
I would also recommend getting the blue stop squeal stuff. It must dry for 15-20 minutes to cure (the can says 5 min), and then you really should be extra careful driving for the first 15-20 stops from 60 mph. Take it easy on the brake, especially if you have ABS, otherwise it will wear right off before settling in and filling the gaps in your pads/rotors that tend to cause squeal. As always, be smart and don't let your pads wear down too low! Check them before and after hard drivin`.
If you're planning to do coilovers (which is the only logical suspension upgrade, IMO) you should do the camber adjustment kit. It's much easier to corner-weight and balance your chassis with the camber adjustment kit.... otherwise you have to lower and raise the spring perches to adjust camber. It makes it a lot easier to corner weight the car if you have at least the rear camber kits, if not all four... because then you can corner-weight the chassis, and then turn around and have a shop dial in the camber you want. I like my setup, -1.8 degrees front, -1.5 back, but it could be better balanced if I'd gotten the kits (see my www).
Oh... and alignment, corner-weighting, etc should be done with YOU IN THE CAR and at least a ½tank of petrol, always.
I don't know anything about the reliability of the kits, but I know that some are/were rumoured to fail under racing conditions. It's basically a plate, with two holes in it... one lets you slide the adjustment, and then bolt it down. The problem is metal fatigue, when you're pitching the car into hard cornering maneuvers. Things like the camber adjustment kit, I would think, become the weak point in your suspension geometry. Or I could just be misinformed. I might look into getting that upper control arm thingy first, and then, when you're doing your lowering, do camber kits on both the rears, or all the way around. At least ask someone who has some autocross or road racing experience what camber adjustment kit to go with. The guys at suspension shops are on commission.... try to keep that in mind when taking advice from "tuners".
Feel free to IM or email me, and check out my www.
