Hi,
You can add simple bolt on's to the engine to get a little more power like a cold air intake, header, ECU reflash but honestly I'd recommend not increasing the power output of that engine only because the transmissions in Pilots aren't the most reliable in the Honda line and any increase it power will shorten transmission life.
As far as the suspension goes you can get adjustable shruts or aftermarket struts that will firm it up a little. There are too many options to list here but a google search will give you results you need.
If this helps please click "accept" thanks! Feedback is greatly appreciated, my reputation is important to me.