bad vibration after 50 mph....

[LBK S13]

I just installed a new header, hub centric wheel spacers, oil pan gasket, 10.2 mm plug wires, intake piping, ported by 1mm intake and polished deleted all emissions iacv... black black, and some strut braces and chasis support. After it was all done I go drive and it feels like I'm in a washing machine on spin so I took the spacers off put wheels back on and the problem was still there so I started removing brces and trying to track it down. No loose bolts motor mounts are good granny mounts are good my drive shaft has a lot of play in it. Like you can grab it and turn it about 1/2 inch before it catches in gear not in gear doesn't matter so I ordered. Z1 lightweight drive shaft to see if thts the problem.. any other ideas?

Clutch is spec stage 3
Flywheel is fidanza
both have about 1500miles on them
Thanks guys

[iLagX]

Bad shocks
Bent rims?
Unbalance rims
Used tires? Humps or bumps can cause this
RAck n pinion bushing tie rods
Ball joints
Alignment

[LBK S13]

Shocks show no sign of being bad. I had them out the other day to put new springs on and they all seemed fine. I didn't see any wheel weights that fell off so I think wheels should be good I have one tire that's getting bad and I'm gonna change that tomorrow as well but it wasn't really doing it before. I'll check ball joints and rack tomorrow after the new tire....camber was a bit more on pass side than driver side. Thanks for your reply any information is useful I'm not a noob or high school kid but I'm also not a master tech at a shop

[jessegrover]

On my eclipse I had a few years back I had the same problem, It turned out to be a bent rotor, you couldnt tell untill you put something flat across it.