What APR to expect?
 

As I've read in another topic, standard APR for such a hot car should be above 7%, financing it with Acura/Honda. Is it true? Can I expect normal 3-5% APR depending on my credit score and higher downpayment? Or should I go and start searching for a better loan for this car? Thanks in advance.

Just my opinion
 

You should always start your financing options with your bank, credit union, etc... You take that to the dealership and see if they can beat it. I believe in people finding good deals.. good deals don't come looking for you.

I get a preapprove loan from credit union for 60 months. They gave me 5.25% for my 2004 TL

If you have good credit, you should be able to get a decent interest rate. My credit union has 60 month new car loans at 5%. I was able to get 4% for 60 months at the dealer. So doing your homework helps.

I got 4% at the dealership with an "outstanding" credit rating (as the GM put it )

I'll say it again....do your homework. I got a much better interest rate at the dealer than at my bank or most other places I looked. I got 3.84% for 60 months.

Any suggestions on how to get dealer's APR lower than everywhere else?

Same way you negotiate a lower price for a car. Haggle.