Couple questions on a 97 civic
 

I have a 97 civic hx, and i have 2 questions i need help with. First of all this car only has 30k miles on it, it belonged to a family member before and i just got it. the first question i have is im not sure if this car is a vtec, i was assuming it wasnt but when i changed the plugs and filters the correct sizes were listed under vtec, can someone give me a quick idea of the benefits of a vtec? 2. also at night when i turn my lights on the rpms float and the lights dim, as if the altenator is charging and dropping, i had a crx about 15 yrs ago and for some reason i think i remember it doing the same thing, can someone shed some light(no pun intended) on this, is it normal, is it a prob? thanks and thanks for the site. chris