I've bought two aftermarket 2-1 header pipes for my 93 EX. One was a cheap eBay part, the other is Bosal's premium line. Both have an exhaust collector of 1.5" inner diameter. The only reason I bought the Bosal was because the cheap one had such a small collector, I figured it was just terrible design.

The stock collector is 1.875". It seems to me a 1.5" collector will severely limit high RPM performance.

Is it a big deal?