@CatHerder
Will your Amiga run slower with an LC chip? Absolutely not. Will it run slower if you use specific applications requiring, or benefitting from an FPU? NO. The only time you will notice ANY problems is if you intend to run Unix on your Amiga (an A3000UX for example because Unix requires a MMU). Other than that, there is no "bad thing" about having an LC chip in an Amiga.
68040/68060 Amiga requires MMU for proper DMA operation (DMA + CopyBack cache). The reasons are described in the
Enforcer documentation (in the Enforcer.guide: 'Enforcer', 'Important 680x0.library developer notes' and 'COPYBACK mode and DMA').
Naturally you can run the system without copyback cache, but the performance will be poor then.