corporate karting can give the closest racing possible.
If your looking for close, fair racing cororate karting is where you should be going.
I do a lot of corporate karting as I cannot afford to run my own kart, no matter how much I want to. I am very lucky though that my local track has possibly the best maintained fleet of karts in the country and some of the quickest drivers you could ask for. The combination of this and the ability to weigh up the drivers has given me some of the closest races imaginable with less than a second separating the top 4 drivers when the flag drops. This has given me the opportunity to work on my race craft and overtaking skills that I might not have been able to develop somewhere else.
The problem with competing with your own kart is the gap between the wealthy and not so wealthy. The people with money can afford to change there tires each session and keep there kart in tip top condition, meaning there kart is as fast as it can be. Whereas the people who are just scraping by are having to make a set of tires last as long as possible and put up with minor problems with there karts. This means the wealthy are almost always out front whereas if you find a good corporate track there will be nothing between the karts.
this is why it is crucial you find a good track, I have found the less money business focused a track is the better as they ae more focused on giving you a good race than they are about getting max profit out of you. My local track replaces there karts very regularly and keeps them in perfect condition, this means there is less than tenths between the fastest and slowest kart. Most decent tracks can weigh up the karts too taking any possible advantage away.
So if you are trying to get into karting, find a good, technical track that maintain there karts and you will have some brilliant races and will find out how good you really are.