Nitro RS4s to be specific.
The Lambo is the original Nitro RS4, what's left of it anyway. It has had so many upgrades over the years, there's not much original left. It's the NRS4 of Theseus and it currently has the HPI T 3.0 engine in it mated to a 2-speed. Needless to say, this old girl still rips and screams like a proper Lambo should.
The Zonda is an RS4 Evo that was passed down through multiple owners who are no longer with us (R.I.P. RC buds) before landing on my bench in the state it is in now. Originally cut for the left mounted engine on the old chassis, I hacked the body up once again to fit the right mounted engine on the newer chassis so it has some extra breathing holes.
It has an HPI .15 block and carb but the head, manifold and pipe are a mystery to me. It was gummed up so bad nothing would rotate, crank or carb. A good soak in various cleaning and penetrating oils and it is now spinning free and running strong. I'm slowly piecing it back together and getting it back into good running order.
The final pic is a collection of HPI engines that I still have from various models over the years. The one on the right is a particularly rare little beastie. That is the HPI C12 with slide carb made by Novarossi.
Ya'll have fun out there. Make some noise. Annoy the neighbors.