LOL...That's too funny!!! But no worries, you'll love it once you get it on there.

 

Here's what Coast says about their 4":

It has come to our attention that our competitors have expressed concern for clearance issues on our 4-inch aluminum driveshaft. They claim that their 3-1/2-inch diameter driveshaft is a better product because our 4-inch aluminum driveshaft has clearance issues. These claims are in-fact unjustified. We have sold hundreds of these driveshafts without a single problem. The only situation where clearance would possibly be an issue is when an aftermarket shifter has been installed.
With all things considered, our 4-inch driveshaft is actually a much safer design than the competitors' 3-1/2-inch driveshshaft. The key factor is the called "Critical Speed". Critical speed is the single most important aspect of driveshaft selection. Critical speed is simply the maximium speed that a driveshaft can spin at safely. Depending on the length, material and diameter of the shaft the critical speed can vary widely. The criical speed of the competitiors' 3-1/2-inch shaft is 6,963RPMs, while our 4-inch shaft increases the safe operating range by over 1000RPMs to a critical speed of 7992RPM. This increased safety margin is well worth the 1/4-inch reduction in clearance.

Still skeptical? Here's what the "Pro's" have to say:

"Because we were concerned with the rotating masses in the S197 we knew there was a very heavy two piece driveshaft. By working with this company we have been able to shed twenty-two pounds off the rotating mass in the driveline. We use their product in all our S197 Mustang’s; now Coast driveline has brought their product to the market with great success. This to me is a good example of how a relationship should work. Their products were tested hard, modified and retested in our road course work. Changes were then made and the end product is better for everyone, including the BDX production cars."

 

I'm going with Spyder in the future.

 

Spydershaft here & loving it