The new stangs are deep sump and recommended every 10k with the partial synthetic motorcraft oil. Every 4k is way too exccessive especially with AMSOIL (SSO is rated at 35k, Non-SSO.. every 25k miles).
Yes the 2011's don't need that, but the oil pump system is different on my Cobra. It's got a 7 qt pan but that doesn't mean I can change every 10K miles. I like to keep the oil fairly fresh since the motor loves to rev.
1993 LX Coupe
Show: Front 18x9 Black Bullit wheels, Rear 18x10 Black Bullitt deep dish wheels, Cervini's 2.5" Cowl hood, Autometer Phantom 10K tachometer, Autometer Ultra-Lite carbon fiber FP gauge
Go: GT40P Explorer motor, Edlebrock Performer intake, AFM 4" Power Pipe, TFS Stage 1, ProForm 1.6's,Granetelli 24lb MAF, MSD Blaster Coil + distrib, Taylor Pro wires, UDP's, GT40p long tube headers, o/r 2.5" H pipe, 2.5" cat back w/ Flowmaster 10 Series mufflers, 3.73s