If you leave the stock thermostat in there it will be fine. Why drop a cooler one in? You could also leave the Seafoam off for now. That alone will net you enough money to get the proper LIM gaskets. Either get the alum. ones or don't do it at all IMHO. Those plastic ones may not make it to August and then you'll really be broke as fvck when you screw up the motor by spinning a bearing. Lets see, $40 LIM gaskets now or $500+ motor later. Have you even called a dealer to see what they want for a set? IIRC, they were only $45 last time I got a set. Check Rock Auto as well for good prices.
And txslow6, not sure what you mean by "coolant o-rings", but the UIM gasket is all one piece, including the gasket area under the TB.
You can still clean the TB w/o removing it and save yourself the $4 TB gasket. Just get some actual TB cleaner (there is a special cleaner for this that does not remove the special coating in the TB. DO NOT use carb/brake cleaner on it.
And yes, black RTV is a MUST, as it must be used in all 4 corners of the LIM gaskets where the LIM meets the heads.
