If you pre-order something on PA and choose Paypal as your method of payment, they will charge you immediately where else they will only charge your CC when the item becomes availabe (in stock) when you choose credit card as your method of payment. IMO, I prefer Paypal since it is safer and they have some buyer protection stuff.

Anyways chances of customs holding your items are rather low of you make purchases which are below a certain value (around RM 500 me thinks)