I don't think there's any truly good coilovers under 1500, or even 2000. A high quality set of shocks/struts and springs of your choice would be more bang for the buck.
Agreed. For a daily/occasional track car, I would rather have the best shock and spring combo available with lifetime warranty than an entry level set of coilovers. However if I was going coilovers at some point I would head straight to Cortex.
http://cortexracing.com/product/xtr...ont-single-rear-adjustable-2005-2014-mustang/