You can buy a spring/boot kit on amazon or rockauto for about $30 vs the $350 you'll pay for a whole new set of coil packs. And yes OEM is the only good option here.
I'd do a full tune up to include the new boots/springs, autolite 103 plugs, new fuel filter, new air filter or clean yours if you have K&N or whatever etc... Its not hard or expensive. Pull the COPS out, rebuild them, plugs are easy and I've done a detailed write up if you've never done them, fuel/air/oil filters are easy too. You can DIY all of this for under $100 easily and it will likely fix your issues if the car just seems to be down on power and not as responsive as usual.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.