I recently ordered a 4000 watt Mono amplifier (2000RMS) and got two Audiobahn 15'' subwoofers that are rated max power of 2600 watts (1300 watt RMS) and I want to put them in my truck, but not using a conventional truck box enclosure. I am going to "modify" the rear metal panel that is below the back glass and separates the cab from the bed of the truck and put a normal car enclosure in it so it can breath better. The subs will be flush with the back cab panel and the box enclosure will mostly be in the bed of the truck up at the front (all which will be sealed up ofcourse). My question is will I run into any problems as far as distortion/clipping with it? And if so how to go about correcting the problem. It also will have a 2 farad capacitor hooked to it and the boxes dimensions are a Vented 17" h X 20 1/2" d X 40" w Box

Clipping would only happen from your amp. It is a waveform where one of the patterns is removed above or below normal. Clipping is not a sound. Personally I think 15's are way too big unless you want to be heard from the next state over, especially for a truck. Moreover you are surely going to lose your hearing down the line in life. Make sure they are phased correctly and only build or use box that is only just big enough for your speakers. People commonly use huge boxes(3-4 c/ft) when they should only be 2-3. A box is very important to the tight ring you want to hear. If possible, separate the two cavities of the box.