i know what you mean. the first time i drove my kart (its only a 100cc 2 cycle) it was just soooo good. it made all that saving money and travelling to the other side of the country totally worthwhile. what spec kart do you have? i would imagine that it is a 125cc 2-cycle?
I have never driven a shifter kart to compare, but i suppose you are right. You absolutely must keep your speed up as you cant just shift down a gear...but i think when you are going as fast as the top boys you will need to be concentrating just as hard on keeping your speed up in a shifter too.
I cant bull shit you either though. i've been racing since 2002, but i probably have the same, if not less track time than you due to time and money constraints. hell, i never even tested my kart before i started racing, that was frigging scary. of course i've done a lot of indoor racing, but that cant be compared. Dont worry too much about your pace in the twisties, that will come with time. Its amazing how quickly my lap times improved after just a few races. Im still nearly 1 second off the pace of the front runners, but i only really compare my pace with people who have done the same, or slightly more race meetings than me and in that respect i consider myself to be doing well.