in terms of horsepower, very very little improvement. if its pretty much a stock setup (no fuel system upgrades, or major power gainers(intake and exhaust are okay)) then stick with whatever the manufacturer recommends. if you do have some major power gainers or are planning to buy them, then buy the absolute best ignition system you can afford. you're bound to make more improvements from there so just spend the money one time instead of continual upgrades to your system.