Re testing, jmo, but I'd wait unless you have a program you're trying to get him into that requires it. I'd wait simply because the reliability of the tests goes up slightly as your child gets older - having a set of WISC scores is going to be easier to advocate with than the WPPSI etc. Even if your child does well on the early testing and you're confident in the results, school staff may question them.
polarbear
I wouldn't really do any in depth testing as of yet I don't think ... but Northwestern University Center for Talent Development has some good class offerings for kids starting at age 4 I think and if he qualified, we could put him in one in the Fall to see how he'd do. They do KBIT-2 and KTEA-II brief form for $120 to qualify for their program (if you haven't done other private testing). So we would have some idea of where he's at and would have a shot at their classes if he qualified and the cost is doable.
And one of their testing places is only about 5 miles down the road from us! Just 10 months ago there would had been no way of getting him tested. He just didn't have the patience, will and overall was just all over the place but right now I think he's in a great place and could do well enough to at least get a decent idea of where he's at. So, yes, the testing wouldn't be for nothing ... it would be to qualify for the gifted classes from Northwestern.