3-tier system is for large users and more scalability.Maybe you only using few client is faster than 3-tier system.But more user is faster.
Using Delphi,you can use different technical,such as MIDAS,VisiBroker and so on.That's depend on your system.You can read three books which are writen by LiWei from TaiWan.
I think that's useful! Good Luck!
