front end mod questions

[puddleglum]

Hi all, I'm new here and could use your advice. First, my car came with a bug deflector installed. I haven't read any comments about them yet. Is it something that is likely causing drag or may it be helping. It is angled back like the hood but definitely causes the air to detach from the hood. Also, I've been running a 90% grill block on the lower opening and ran a 90% block on the upper in the winter also with a flap that could open another 20% or so. I was okay in town but was too hard to adjust on the highway. I cut the flap of and am just running the 70% block on the upper. I need to redesign the whole system i think so I have some more adjustment for air flow. If I redo it should I be looking at keeping the bottom open more and blockmore of the top or keep it the way it is. I also installed a cloroplast pan under the engine compartment to help keep a little more heat in and was hoping for a little aero improvement also but I'm not sure I did it right because it didn't seem to help mileage any. It also transmits alot more drive train noise into the car. Is that normal? The existing pan drops from the front bumper which would be directing air underneath the car. Would it be worthwhile to try install an air dam underneath the bumper, or is alright to have a pan that's high in the front and slopes down?