I really want to remove my splash shield. I read the other thread where people said no problems. Here in Arizona, seems like a good idea to get rid of some heat.

But... Would the resulting increase in dirt and grime cause eventual heat buildup anyways? I look at how clean the engine stays and it seems like the splash shield does a lot in that area.

 

Can not see there being a big benefit - unless you are racing and can open the hood to let the heat out - then I can see where having the bottom of the compartment open would help. But if you are driviing under normal situations all air movement is front to back and the belly pan is open at the rear.
Keep it clean and more important dry.