WS6 Cruiser

Hello all this is my first post, Well I just bought a 02 WS6 Auto, with 35K miles. I just took it into the shop and had ARH longtubes, Magnaflow catback, new plugs and wires, 160 thermo, and dyno tuned. Made 342.12 hp and 355 tq, power fills good for right now. Here is the question after having the mods installed every time I turn mainly right and give it some gas something under the car maybe a sway bar feels to be silping or moving, does it also when I punch it off the line. I need help I have no idea what it is, I bought this car as my first hot rod/weekend car, now I just need to figure out what is wrong so I can go have some fun. Any input would be great. Thanks

killagt

iTrader: (3)

Im thinking you need suspenstion upgrade time heheh.

antsls1

iTrader: (3)

def something in suspension

DNOBLE1

iTrader: (8)

Control arm bushings? If you're driving along and mash on gas and then let up does it feel like it want's to go left and then right? If so then it's probably time for new control arms.

Undertow74

iTrader: (45)

Or mabe your PHB is coming loose.......check to see if there is a Adjustable PHB mabe the jam nuts came loose, had that happen before. Check to make sure your rear is centered.