Do all of the maintenance, oil, spark plugs, timing belt, brakes, ATF etc if they haven't already been done. Put a cold air intake in it maybe, don't put a loud muffler on it unless you're into loud/harsh four cylinders. Then push it off a cliff if you want it to go faster.
In all seriousness, having driven my late grandparent's '96 Cirrus with the same engine right before it met its rusty western Pennsylvania demise, just be happy it's still on the road and treating you well. And save up for something else. A car even 10 years newer in that class will feel light years ahead performance wise.
Or SRT-4 and/or manual swap, because I am a bit of a Mopar nut.