You DON'T have to brew from kits -
look through the recipe sections - find an IPA that sounds interesting and follow that. You can order everything individually...
and for what it's worth, most IPAs are dry hopped. Bitterness doesn't fade much - it's incorporated into the liquid more completely during the boil, but flavor and aroma most certainly disappear over about a 3-month window.
I also agree with Shooter - carbonation will change your perception.
So, for the OP (lpstudio18) - your choice. keep to the kit instructions, or make an IPA.
English IPAs use the European hop varieties, while the American IPAs primarily use northwestern varieties, those mentioned above.
Depending on how much you love that aroma & taste, try one ounce for a week, two ounces for a week, or two ounces for two weeks - of course you can vary that to your liking, but call that 'light', 'medium', 'strong' for a starting point.
Oh, and it may be "duh" but dry hopping is done after the fermentation is complete. Some say dump the hops into the primary, but I have found that the trub seems to absorb some flavor, so when I dry hop, I either use a secondary or dry hop in my keg.
If you want the hops to slap your face, look for the Pliny the Elder recipe...