Considering the iPhone 3GS (among other phones) 

Now using 012 number but already switched to DIGI, and planning to buy from Maxis reseller at full price, no contract. Need some help with these questions:

1. As the phone is officially unlocked, there shouldn't be a problem using it with DIGI's data plan right?
2. Will there be any problems obtaining and installing apps (with a DIGI sim and digi data plan)

Thanks.