i'm considering either an euro 321hp engine or a supercharger for my 99 m-coupe. the euro engine is around $13000. but if i get the that engine, i can also sell my old engine (for about $7000 market price) and end up paying $6000. this is about the amount i'd have to pay for a supercharger. so does anyone have any ideas or comments on reliability, performance....etc. thanks!