Chau,
A quick heads-up on the KA Classic Series.
First off, the dough, at a certain weight, tends to crawl up the hook into the springs that holds the hook in place. Second, the bowl "locks" tightly in place on occasion where it almost takes two people to get it out.
If you want to spend $200-300, look into the Cuisinart 5.5qt or 7qt, with 800 watts of power or get the Bosch Universal, the new one, or a DLX. They are all much better mixers than the KA, imho.