I have a 2000 5 spd lude. I got a custom bent header with a 2.5" collector and I ran 2.5" piping to a 2.5" magnaflow muffler. I also have a v2 and some pulleys. However the other day I drove my friends stock lude 1997 lude and his felt like it had noticeable more torque low down and I couldn't really tell if there was a difference in vtec as I only hit it once. But his lude def climbed hills alot easier. Also in first gear I only had to rev to about 2500 rpm till I felt like i had enuf speed to shift to second. In mine I have to rev to 3000 rpm. I didnt say anything to him but i felt like crap after all the hard work i put into my car. Is my 2.5" exhaust too big for a NA lude? Should I invest in a smaller cat back system or shud i make the diameter smaller right from the headers?

Thanks!!