do i need crossovers on a 2001?

 

Your infinity reference coaxials should already have it built in, I think. Do they only have one set of terminals (+ and -) and leads and a capacitor going to the tweeter?

 

yes there is only one set...

 

Then the tweeter should have at least a capacitor in line with it and possibly a coil as well. Usually, coaxial speakers (woofer and tweeter in the same frame mount) have the crossover wired in from the factory. Component speakers (separate woofers and tweeters) will typically have a separate (and typically more complex) crossover module to wire and install.