Hi AVI LT,
There are many threads on this site about changing the upper cladding to the smooth EXT style cladding some with photos.
Basically if all you change is the center section with the larger light you will have a gap at either end if the section. Most have not chosen to live with the gaps so they then have to change out all the upper cladding pieces from sail panels inner and outer, to storage box lids and tailgate trim. It will run you anywhere from $1,500 to $2,000 in parts not counting the purchase of replacement retainer clips since they tend to break when removing the cladding. You may also have painting costs to get the cladding the right color too.