Do I Need To Have A Tune

Just bought the Bassani Cat Backs & the X-Pipe with Cats. Can I install them both without having a tune done on the car? I know that a tune will make the most of the modification - I just need some time to refill the piggy bank. Was hope to run the new exhaust for a couple of months, then install a CAI (C&L) & gears (4.10s) (set-up recommended by my local performance shop). vr.....moondog