WOT vibration after eibach install???????

I recently added Eibach springs to my 04 GTP and now I notice a strong vibration under heavy throttle especially around 60 mph and above. Is this common? Does it have anything to do with the axle position being lowered? At first I thought it may be harmonic and exhaust related. Any suggestions would be appreciated.

This is my first post and I havn't fine tuned my registration but my mods are standard: CAI
3.4 pulley
MSD ign.
cat back dynomax

p.s. I don't know if this is applicable but I accidentally damaged the r/r abs sensor and had to replace the r/r hub assembly but prior to installing the new hub I disconnected the battery overnight to attempt to reset the trouble code. Didn't help, didn't matter I had a real problem.