Confused on thermostat replacement. First pic below is from the manual. Number 2 is the seal that fits on the thermostat. It shows no gasket where the two parts bolt together. Next pic is the metal upgrade. It shows two gaskets (a four hole to the block and a three hole between the two pieces). Does the plastic original not have a gasket (other than the round rubber seal)? Not sure what the other two round seals are in the second picture. Thought they were the cross over tube to the heads, put they don't look the same.

For the cross over tube to the heads I found part number W0133-4061531. Is this right? Are they the same left and right?

I still have the plastic setup and read all the posts on these cracking. Would really be afraid to try to loosen the bleed cap on an 18 year old car. Going to upgrade to metal. So if I get the kit below, do I still need the cross over tube to head seals?

 

The original setup only uses the rubber seal that fits onto the thermostat itself, no other gasket is needed

As for your second picture showing the aluminum setup - the rubber seal closest to the housing, this will be for the thermostat itself. The other rubber seal closest to brown gasket, this should be the seal that goes into the bottom of the thermostat housing. It looks like they will supply both?? The original ( factory ) set up only uses the rubber seals. The supercharged setup for thermostat housing is all aluminum and only used the rubber seal, so I think you should be ok.

As for the cross over pipe seals, they are the same size from one side to the other. And I would change them if you're removing it, even to just gain access

Hope this helps

 

Had exactly the same confusion myself until I took it apart.