When i fitted an Allisport full width intercooler, I began to experience slight overheating in the summer months due to the flow of air to the rad being restricted, I replaced it with the 40% one. Also fitting one will limit your front winch options due to the lack of space behind the grill caused by fitting it.
Do the tweaks yourself, just make a note of the original settings first, so you can take it back to standard should the need arise. The EGT guage is definitely a good idea also..