I have had 3 Fusions I know the kit ball bearing are cheap and do not last if you really run your car. I replaced mine with boca bearings. The clutch will hold up fairly well with the stock motor but not with a highly modified motor it slips. And your 3-speed tranny becomes a 2-speed with a highly modified motor because the torque of the motor causes it to start in second. Since the tranny is non adjustable you cant compensaite for that. When I started putting highly modfified motors in my Fusions was when the reliability problems occured. But don't take my word for it just sharing my experiences with you you may have better luck so go for it. I mean you could make it really run if you have the desire but it is gonna take alot of work and time to correct all of its short comings. Here is a picture of my Wolfpack Fusion with RB modified RB .21 motor, wolf adapters for 1/8 scale tires, modified clutch and special belt and pulley system to reduce rotational mass and friction on the drivetrain. All time best 90 mph almost drove it outta site to reach that speed, average speed 88mph.
