Inside the box there's a booklet named HTC Premium Navigation, and there's a serial number in that booklet. Pretty sure there's instructions too on the booklet.

Once you use the serial number (voucher code), you will be able to use the licence for life (make sure you enter the CORRECT IMEI of your phone) with an additional 30 days voice navigation. After 30 days you will need to purchase if you want the voice navigation.

how to install application directly to my SD card after i root with LeeDroid?

For existed application, sometimes i use manage application and try to move to SD card, but still got some data left in phone memory ..
and if i install a lot apps and it look like eating up my ram a lot.
when i check running services look like a lot is running even task manager show closed.

left only 50ram average >.<

Look for Apps2Sd in the market. But more often than not even if app has been moved to SD there will be data remaining. As far as I know for best performance leave your apps in the internal memory. Another solution for you is to not install too many apps. Think of it this way, in a week, how often do you use that app, if you've never used it in a week or only a few times for special occasions might as well uninstall.

and for clarification, running services are services/processes that run in the background. The stock Task Manager will only show you open applications. It's similar when you open up task manager in windows and you click the "Processes" tab, those are similar to running services in your phone. There are ways to kill them/freeze them and one is through Titanium Backup.

should i flash recomended radio by Lee ?

currently using 3.0 rom with stock kernel.

do i have to reflash my rom and superwipe?

Anyone sent back to sis to fix the dust under the screen problem? Will it come back again. Mine got minor dust but my friend's is like damn bad. Extremely lot went in. Anyone having the problem again after fixing? Thanks.