as far as speed bumps and potholes..... you would more then likley want a better shock. edlebrock ias are nice shocks, but cost 75 each. second imo is monroe sensatrac shocks, i had those before i lowered it, well i still have them, because i cant find a 4.5 inch drop shock, have to go custom that way.
also you would get far better handling around turns and braking if you replace that thin ass sway bar with a beefier one from explorerexpress.com they have many things for your truck, just becarful dont get the drop kit there, way to expensive for 2 inches.if you lower it it would handle a bit better on the bumps, it wouldnt wobble , but it would be a firmer hit, (less travel in the suspension.) you have any other questions id be glad to help. good luck with your explorer.