I really hope they find three new slightly odd characters that have great interactions over their love of cars. That's what set Top Gear/TGT above, plenty of shows have fast cars, cool shots, informative reviews and comparisons, and even silly bits. The magic is that it's about your relationship with your vehicle, your many interactions happy and devastating, and the adventures you go on together. Don't try and replace the trio, don't bank on a famous face, but get three people who can voice what a car actually means to them, whose differing perspectives on the same path paint a more vivid and real picture, and you'll have a worthy successor.