I added 3x Rishkar, Peema Renegade and it has been a good addition, and I added 2x Gonti, Lord of Luxury and 1x Clear Shot (for 4x total in the deck). To make room, I removed 1x Aethersphere Harvester, 1x Yahenni, Undying Partisan, and all 4x of Night Market Lookout. I really, really LOVE Night Market Lookout, but I have limited the vehicles so much that its utility is quite low. It's great that it does damage just by tapping, but a 1/1 without any real protection (e.g., deathtouch) is virtually a wasted card, and something had to give to get some better options into the deck.
If I still had the 9 vehicles with crew cost of 1 in the deck, no question that Night Market Lookout would still be in the deck, but the deck has morphed much more to a "deathtouch, with a hint of lifelink" sort of deck. That means that vehicles aren't a good part of the deck anymore, though Aethersphere Harvester has more than once been the shining star because of the lifelink.
It doesn't show up often with only 1x, but when Untethered Express hits the battlefield, it is a huge impact vehicle. This is a vehicle that I may look at getting up to 2x or 3x total into the deck. Huge impact factor.
The combat tricks like Blossoming Defense and Clear Shot have been awesome. Clear Shot in a deck full of deathtouch creatures is amazing. It's instant speed, so I can use whenever I want, and I can use it even if my creature is tapped, giving me double damage with the same creature. Any damage done with deathtouch is fatal, so using Clear Shot on my 1/1 deathtouch creature and targeting my opponent's big creatures means my 1/1 (2/2 after Clear Shot) kills their 4/4 or 5/5 creature and I don't lose mine in the process. Clear Shot has definitely bummed out more than one opponent. Excellent card. Thanks to bunnyplasm2 for the great suggestion!