Deckplate Mod

Ok, so I was interested in the deckplate mod but i have a few questions.
1.) What is the best size deckplate i should use?
2.) Is there a gain in horse power or mileage?
3.) Do I have to cover the hole when I drive in rain?
4.) If I have the flowmaster exhaust, will I hear any difference in my truck?

Thanks for all the help!

 

http://www.trdoffroad.com/articles/deckplate/index.php

This answers most of your questions

 

i will make it simple right here for you, but the search button is your friend, lots of DIY 1st gen mods under the 1st gen section.

1. 4"
2.Supposidly a little bit......There is a dyno somewher around here, it honeslty just sounds really freakin cool
3.no i dont, only if your going to be doing some major water crossings or hitting mud puddles at speed.
4. Possibly but prob not enought to notice, you will hear more of a roar from under the hood.