83k maintenance time ( input and advice needed)

[Edsel1134]

So I finally found a new dd/track car to allow some we deserved down time for my g8. Clock is mid 80k miles and what are so maint things I should start looking into?
Sub frame bushings?
Belts?
Aside from the obvious plugs wires stuff
I know this saying if it's not broke don't fix it.. But preventative maintenance out rules that.
Mods are as follows
Rotofab
Kooks mods hfc
Solo Mach shorty. (Best exhaust system eveeeer)
Bmr front and rear sways (need to finish with sway links)
Aside from oil changes plugs and usual stuff I'm at a stand still. I have developed a clunk every now and then since sway bar install in the front. Maybe bad end link since stocks are weak.
That and every part shimmy and rattles on a cold start on the the car.. Dealer has "fixed" and failed to replicate several times (lazy ***** ***** *** ***** gm *****)
So any thing that comes to mind will help, post diagrams pictures what ever u want thanks

[-Ray-]

Plugs I guess. Take the wires out and put your ohm meter to em. I've checked my wires every Winter, and they haven't changed a bit. Now that 4 of them see heat from a turbo that may change.