The most common advice is to buy whatever is supported in your area, but based on where you live my guess is that you have plenty of options. From there you can go any way you want. I have owned 2 CRG’s, both fast. If you go with a CRG I highly recommend the ceramic brakes. My current CRG has steel, and they work great but the ceramic are lighter and they felt better to me. Anything that is built by CRG or uses their brakes would be similar, meaning CRG, Zanardi, Energy, DR, GP, etc. As a side note, DR kart parts fit CRG’s and can be cheaper as I have recently discovered.
I have no experience with Tony Kart’s other than thinking they looked fast when they passed me. Tony’s are popular, but from I have seen they have some of the most expensive replacement parts.
Intrepid’s new karts look nice, and their new shifter is priced at $4400 brand new, significantly lower than others. I am looking at a new or newer kart in a few months, and the new Intrepid is the one I am currently set on.
Arrow has introduced a new shifter model, but they do not seem to have a huge following in the shifter market for whatever reason, despite their success in TaG and other classes.
Whatever you pick, one thing that I have learned is that a clean straight chassis that is set up and maintained properly will be as fast as anything else on the track with the right driver, regardless of what color the frame is painted.