Subframe connectors are $400 for parts plus labor, never heard of that brand before. So no, not expensive. That pic of the rear looks like the control arms are stock... I hope you didn't pay for "premium" suspension.
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 ****.