I'm not familiar with these engines, but I would assume that they would respond well to the same mods as any other car. Exhaust systems and Headers will make a difference, especially at higher RPM's. Don't upsize the exhaust system, try to find a header/exhaust with the same diameter as your stock set, but with a less restrictive design, IE; less sharp bends and less noise reduction devices. An ECU tuner can provide a good power gain at a cheap cost, but I'm not sure how well it would interact with other performance parts. Do basic stuff, like filters and fluids. Check to see if there is anything that can change the transmission behavior to a more sporty shift type. Look into getting a set of nice sports tires, more power wont help if you are running cheap economy tires. Weight reduction, if you don't take the car anywhere where you can't readily get help, or aren't concerned about becoming stranded, remove the spare, jack, or other heavy items from the car. A word of warning though, Most engine modifications will cause you to fail inspections/emissions testing. Depending on where you live, removing items like the spare, jack and roadside kit may also fail you. Good luck, hope this helps.
