I have a 01 Bullitt with factory subframes. Would it make a big difference to get aftermarket subframes? I am building my car for windy roads and handling.
Get good subframe connectors. The factory ones dont really do anything. If you take them off and look at how they're attached and the thickness and type of metal they're made from you'll see. Thin walled brittle metal attached with 6 bolts. Your car will feel so much better with good welded subs.
The Bullitt subframes are junk. I cracked my passenger side just from hard driving & road racing. First of all, they're a poor design with a thin sidewall, basically just the convertible subframe connector. Second, they're bolted on, not welded. Scrap 'em.
Now, whether or not it makes a difference depends on how you drive. Quality tires are a better investment for hard driving, in my opinion.