I did win an engine from a four-star ticket lately, but it was my fourth 13B, and I had already swapped the first two into each model it's compatible with. So now I got two 13Bs just sitting around, alongside some other engines I've yet to find a use for, like a second Aventador SV engine, or a spare LS9 from the Corvette C6 ZR1.
Personally? When the Holiday Campaign kicks off tomorrow and I eventually log in for the engine ticket, I'm especially hoping to get an engine that's expensive, namely from the Chiron, or one of the Group C racers. Sure, I've won an engine before from the 787B, R92CP, and the Chiron, but each of those three engines have more than just one car they're compatible with, unlike the XJR-9 engine which I haven't won yet.
EDIT: My bet? I think the LS9 would thematically make sense going into the Pontiac GTO Judge, and then the Aventador SV engine could go into the Countach LP400, the Diablo GT, or maybe even the Murcielago.
EDIT2: Is it ever really worth it to swap engines with one of the Gr.4 cars? I ask because I have a spare engine from the 2008 GT-R GT500 but I’ve already put one into a Z34, so the only other option is to potentially put it into a Silvia Gr.4. I’m aware that you can’t use swapped cars in BoP events, too, but could a swapped Gr.4 car still be worth using in say, the WTC 700? I suppose I could just try finding out myself, haha.
EDIT3: It also seems that upon further research, the 26B from the 787B is the most expensive swap in the game at 1.75m credits. Meanwhile, the Chiron’s engine is tied for second alongside stuff like the XJR-9 engine, costing 1.6m. So winning another 26B when I log in for that six-star engine ticket would be amazing, though I’d be very much content with pretty much any engine that costs over 500k credits.
EDIT4: Honestly, if I win an engine from the 787B, the R92CP, or the Chiron, I’d put them into the Mazda3, R33 GT-R, and the Huracan respectively.