Hi, Would like some advice please.

Looking to do some modes to my S3.

With my budget I'm looking at getting a Forge CAI , Forge DV, and chipping the car. Has any1 done these mods?
What are they like to live with? does the DV give any hastles?

I would love a Down-pipe aswell, but thats out of my budget for now.
Is it stupid do to the intake without the DP?
Can I just add one later without having to remap the car?
Or should the car be mapped with the intake and dp already installed?

Thanks in advance