skidplate
 

on the bottom of my 91 i have a plastic skidplate which looks more like a dirtplate, is there any real reason to leave it on?(e.g. does it protect anything or do serve any real purpose)

you mean the undertray under the engine area?

If you're talking about what I'm thinking (the undertray...I don't really see what else that could be since it's a '91) then yes it serves a purpose and DON'T take it off. Not only is it there for aerodynamics, but "more importantly" it's there for cooling issues. If you want the car to cool properly then don't take it off.

yeah. the car will still cool OK with out it, but it helps the radiotor work more effeciently. also you need it for aerodynamics. get up over 100mph and you'le start to feel a buffeting whith it off, while if its on the car stays smooth up to top speed. i gota find a new one because mine is all shreaded up and i had to take it off:(

Has anyone made a replacement? Using maybe a similiar plastic or even aluminum sheet?

The undertray ensures that air entering the nose is forced through the radiator. Without it air will simply go under the radiator because it's a far easier path to take.

thank you for answering my question i was utterly clueless.

For the record, Mazmart in Atlanta had a few left last time I was there, but they were going fast. For anyone who doesn't have one, they are not expensive (~$25-40 I think) and are considered important to have. I did not have one on my car and when I put in the turbo engine sometime in the next week or so, the new undertray I bought is going on too.