In order to void your warranty the dealer would have to directly prove that your mod caused the fault. With the suspension this may pose a problem if your shocks go out prematurely (highly unlikely) but as for anything engine related really no way for springs and exhaust to blow a head gasket.
Dinan tune is obviously covered so probably the safest bet for a brand new ride and some of the numbers they've been able to get out of the 550 are insane!!
Hope that helps some and enjoy your new car!!
