Yeah it has to be tightened all the way. I would get rid of the bolt on headers and get a spring style header. its the same price and it is really hard to wreck.
I dont know what the other guys that were running FLM CVDs did to wreck them, they could have just been BSing me. I have been looking into them more on a few other forums and no one else has said anything bad, so i ordered a set. I am looking forward to not changing u joints and loosing Eclips. The only thing that i can say about them is the price is a little steep but look to be really strong. Did you notch the pins or anything to make sure they dont move.
Definitely go with a spring mount header. The stock ones are junk IMO. The only prob though with spring mount is you can't run the EZ start which I didn't have a problem with because I hated it and wanted to switch to pull start and glo ignitor.
For the CVD's I really didn't need to do anything to install them except for using some blue loctite on the set screws. They come with a pin retaining ring to hold the pin in the axle cup. There was a guy over at the traxxas forums that bought a set a couple of months ago and FLM has updated the CVD's from the protos that I have and they look like a good update to the parts. Yeah I agree they are a tad pricey but I'm telling you they are worth it. I've had the protos Jamie sent me to test for almost a year now with hardly any signs of wear at all. They are definitely super strong, and I've been beating the crap out of them since the day I put them on without any problems.