That topic is beat to death they have their pros and cons. What exactly are you doing? Stock bottom end? Budget? Goals? "Reasonable" budget for one person is completely different for another person. You will likely spend nearly as much on 4V heads in the end as the TFS heads new or at least a set of good ported PI heads. The Terminator cams are not anything to write home about anyway, the 96-98 Cobra cams were the best OEM 4V cams.
2000 Mustang GT Steeda #0048 34k miles. 99 Cobra 4V swapped, FTBR IRS swapped, exhaust, tuned by James Gordon.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.