Wormy,
I had a yellow top Optima & liked it ... till one day ...
When they go, they go all at once with no warning. Will not charge & will not jump. I'm just sayin'.
IRT upgrades whilst keeping with the 'Urban Mall Crawler' theme: Not really anything to add (other than the obvious such as sound system, alarm system & such). You may find a power inverter useful though.
Knowing the traffic you play in (as I intimately do) you might want to consider a hitch & SuperBumper.
I know you are running a blower & aftermarket rims/tires but I'm not familiar with any other upgrades you already have.
EDIT:
Are you due for AC service?