Duratec 2 litre engines will go up to 220 bhp without internal mods needed by changing cams - relatively cheap , changing manifold to help breathing , obviously doing throttle bodies will be more expensive but that gives you scope to get up to the 220 mark , after that its steel rods /high lift pistons race springs . Mine was 210 bhp and was superb to drive and making all the right pops on the exhaust !