I want to add a plenum but like the steath look.

Which of the plenums allow me to use the stock engine cover?

 

None of them do as far as I'm aware. The Plenum spacers that hydrazine fabricates allow you to keep the stock engine cover with sizes up to 3/8" thick but they haven't had the best success on the 2005 6MT's. I don't know which make & model year you have but if you own a 2003 or 2004 you might want to consider that.

Also, what's the deal with the stock look being so popular? When's the last time you went to a meet and said, "Check out my stock ride. I put a bunch of money into mods and it still looks stock."??????? I always have been and probably always will be a huge Crawford proponent. Doug Stewart found the deficiency with the stock air flow, he created the first plenum spacer and then the first plenum. Just about everyone who's purchased his headers has loved them and the same goes for those who've purchased has his h/f cats. I think it's a win-win-win with Crawford.

Also, I like the modded look. It shows that everyone has a little spice or flavor added to their ride. As always YMMV.

 

You may want to point out the new & improved version of hydra's system.

 

The new spacer I think it's 5/16th with thermal iso gaskets is a perfect match and you can put the cover back on. I know one of the guys in the socal forum has it already "Klumzyee".