I am looking for some advice on engine conversions. I have done plenty of work on impreza engine mods etc but I am new to the bmw scene. I have bought a vgc 98 318i touring but obviously the motor doesn't have much kick and I would like to stick a larger motor in her and was wondering what the best route to go is? Am I better tuning a 2.5 or 2.8 motor? Or am I better sticking an m3 motor straight in there? Which is easier? Are there any points I need to pay particular interest to? Pro's and con's etc? Any and all advice will be greatly appreciated as like I say I am new to bmw so even simple things I might overlook.