While being able to put spiked plating on my spikes is awesome, I am fairly certain that being able to install engines, windows, and so forth using spikes as the framework is an oversight of the vehicle update, not an intended feature.
Ah, yes. My mistake. I made it so you can’t install frames off of spikes in adjacent squares without proper support, but forgot to account for people putting things on the same square as the spikes.
Thanks for reporting, I’ll have a fix soon.