As far as monthly or bi-monthly maintenance - I would apply the Nattys Wax after a washing every month or two. I have been reapplying Nattys to all 3 of my cars about every two months. Actually, my Bonneville had 2 coats of Nattys Red put on Jan. 13 and it is still beading real nice after it rains.
EX or EXP - I use after PWC/PWC Blue/PwS and before the Nattys application. With EX or EXP, you have to apply a very thin coat (microfiber applicator dampened with water) and let it dry for 30-60 minutes, depending on weather conditions, then buff off. After the first coat you should wait a minimum of 12 hours to reapply a second coat or apply your coats of Nattys after that. Nattys you can layer a coat right after another coat.
Nice looking cop car - although if you pull me over.... :twisted: