I have a bit if vicarious experience; trying lawsuits either as an attorney or as a judge for thirty some years.
1. If your state has a version of "small claims" court that is NOT optional and if your claim is with in the amount that will qualify, and if it otherwise fits within your states small claims statute (in some states it may be called by a different name), then as one of our members reported a few months ago, you have a fair shot at prevailing. Unfortunately, many states small claims procedures can be avoided under several circumstances, and typically a corporation will avoid them if possible if the amount is more than a nuisance to them. For example, in some states, the person who has been sued can opt out of small claims simply by filing a notice that they want a jury trial, so if you try to go that way, it may be that all DC would have to do is file a document saying they wish a jury trial and you are back at the starting blocks.
2. If you do not fit the small claims approach (a blown engine is not going to go there), then the effort to apply something like the Moss act is not simple, is not quick, and is not cheap.
Here is the likely situation;
You have a failure and your truck dealer says, "sorry, no warranty coverage because your aftermarket "do-hicky" caused your engine to eat a piston.
You go to the "do-hicky" company and tell them what happened and they say to you, "your dealer has been smoking dope, the do-hicky did not cause the damage. After that neither of them want to talk to you--
(as an aside this very thing happened to a friend of mine when the turbo on his exhaust brake equiped '01 PSD did a melt down;he ended up eating the $1500. it took to repair a truck with 5000 miles on it. )
The only real course of action available to you is to see your attorney. Now he knows what kind of multi-year battle is PROBABLY ahead of him and he knows that before he gets to the end of it win or lose, he/she is going to have to spend $ 2-3,000.
and several hundred hours of time.
Since he is not into working for free and spending his/her own money on your claim, he/she is going to need $6 to 10K up front.
Get the picture? I have been involved in this kind of litigation numerous times. It is not a very realistic approach for most people unless you really have no choice.
If you are concerned about your warranty, or if you do not have the money and time for long drawn out lawsuits (remember, unless you pay out of pocket, no one is fixing you truck while all this drags along for two to four years), it is best to avoid those things that MIGHT get you into this quagmire.
Vaughn