WHAT??????? You don't need a 203 thermostat to run a coolant filter!!! Has nothing at all to do with it. Way back when I bought the kit from Bob ( Dieselsite) for $65 but now that he is asking so much more I wouldn't waste my money. Just buy the parts yourself for about $30. If you do use Bob's kit don't use his ball valves, go to lowes and get some gas ball valves, much better than those cheap ones and they seal 100%. I mounted mine down behind the drivers rear tire, there is a cubby hole there that is prefect and protected, but you will need two of the gas ball valves for changing filters. I also see no difference 8 degrees makes a difference on coolant temps. If you have any ? PM me.
NCH