Im looking for a good quality oil cooler sandwich plate for my 2005 wrx sti.I was keen on the mishimoto thermostatic sandwich plate but ive read bad reviews.Should i rather go with a mocal , greddy , setrab or beatrush sandwich plate instead ?
Have you positively identified that you are in need of aftermarket oil cooling? If you're not exceeding your oil's rated operating temperature then adding an aftermarket cooler would likely do more harm than good.
If the highest oil temp you're seeing is 250°F then you don't need an aftermarket oil cooler. If you're using full synthetic that should be well within its recommended operating temperature. Coolant temps on the other hand.. I would be looking for a better radiator personally. Keeping the coolant temperature within check will also bring the oil temp down some via the stock oil cooler.