The answer lies under the hood.
Whoever owns this custom E30 M3 is really, really high on it. Here are just a few terms, pulled from its eBay listing, used to describe it: land rocket, finest race-focused E30 M3 beast, and the ultimate E30 M3. So, what makes this BMW so damn special? For starters it doesn't have its original engine. That was dropped in favor of a 5.0-liter V10 pulled from an E60 M5. That engine was further modded by BMW tuner Dinan to kick out 5.7 liters.
So its engine is huge, that much is established. However, it also appears the rest of the car is either completely custom or saw a substantial rebuild. At the end of the day it's still an '88 M3 with 30,000 miles on it. Is that enough to warrant spending almost a quarter of a million dollars? We'll soon find out as this thing is racking up a ton of views on eBay and already has three bidders watching it.