Keep in mind that a tune will technically void ur power train warranty. Just about any power mod besides a tuneless CAI, a catback/axleback exhaust and an electric turbocharger will require a tune.
If u only have about a $1000 to spend get ur Mustang planted by upgrading the suspension. The easiest is to get the Eibach Pro System Kit or the Sport System Kit for a lower drop. It will cost $999 or so.
But if you can't install it urself then the kit will cost u about $5-600 for install I believe.
Else a more budget minded approach is Pro Kit lowering springs only ($200-250 + $200-300 install), and a GT500 axleback exhaust ($350-400) + $50-75 install).
I really needed your advice and it was an eye opener. I was almost ready to order an STEEDA CAI. I can't do any big installs( got the brains but no back) your suggestions about suspension work is pretty cool... It's got me thinking in different areas of performance, your price breakdown is right on my $1000 budget. Tks for the help. RR
I dont know if your interested I have 2012 gt cal. spec convt. and have four yellow adjustable koni shocks almost new 1 month old(were $800) and four bbk lowering springs 1.5" (were $300). Will sell both for $400. email@example.com