I got the steeda setup two weeks ago and so far so good, but like everyone says you have to put something on the threads of the FWA to keep it from vibrating. I used Nissan (since I work at a Nissan dealer) RTV Red Silicone (just a drop!) to keep my adjuster in place.
FMS gears don't come stamped with anything, though. That sucks..all they give you is the gears, the pinion nut, and a crush sleeve. I guess they think that if you can get it out you're good enough to get it in right.
it's time consuming, but not overly hard. It's just a precise install process. Took us about 6 hours to do mine, on the ground, with new axle bearings and rear brakes as well as gears. Like I said, it's not hard, just involved.
i held the yoke with a 3 foot pipe wrench while my stepfather torqued with a 1/2" 2 foot torque wrench. You should try to avoid using an impact if possible because you could overdo it. It is best to have someone hold the yoke and do it by hand, but you really have to put some ass behind it!!
c4 is almost bulletproof for an automatic trans, but tends to be a little more on the pricey side when things go wrong. AOD's are good if you intend to do highway traveling because of the OD ratio. I would go AOD if you are doing a lot of driving.
don't be worried so much. if you notice noise, just reshim it in the first 500 miles or so (unless it's horribly misaligned). ford racing gears are known for their ease of install...the hardest part of mine was lifting the diff from the floor into the housing...that's a heavy chunk of steel
check with jet performance, hypertech, or diablosport...you may have to call them to find out about custom programming, but they should be able to help you
the pinion should be set if the shim was already on the new one when you had the bearing pressed on. measure from the head of the old pinion to the edge of the housing with a micrometer or dial caliper, then try to set the new one exactly as the old one was. sounds more complicated than it...
oh, and make sure to add friction modifier when you put it back together!! ford has it for about $10 a bottle (i think the reference # is XL-7) or BG makes some stuff called LS-2 if you can find it. Lucas also has an additive, but I have never used it.
i went from 3.08 to 3.73 and had to add about .006" of shim, i still have a little buzz at 55-60 mph but not enough to concern me. the biggest problem is setting your pinion depth correctly. if your measurements are precise and you use the same location to measure from, you shouldn't have a...
the quadrant would be directly over the gas pedal. i searched for 40 minutes one night looking for mine to see if it had been upgraded from the plastic one. The fork is where the cable attaches at the transmission. Sounds like you have either broken a fork or one of the springs on the clutch...