It's not actually a coil on plug system. Coil on plug puts an individual coil on each plug. The 2000 XJ uses a coil rail with three coils that each fire two cylinders simultaneously in a waste spark system. It works exactly the same way as the waste spark system in the Dodge Viper or any of the Dodge six cylinders, just without plug wires.

The distributorless ignition system gives you just about the hottest spark you can get, and the computer can keep thing running when other setups would have already failed. Failures are not common. In some ways it's a simpler system, in that there are fewer parts to fail.

I had 160K on my coil rail when I swapped my engine after my 0331 head cracked, and the coils were still fine. I went ahead and replaced it with the new motor, but I have it in a box of parts as a backup in case I ever need it. I doubt I will.

LOL no.

Some of them crack just because they're defective. I followed the maintenance schedule to the letter, never abused it and never overheated it. Mine cracked. Quite a few people have had the same experience. Quite a few have also had no trouble at all, so I guess those of us with the crack were just lucky.

As for the other quirks of the 2000, nobody has mentioned yet that 2000 was the year that introduced the crazy California emissions system. In 2000 you had a choice between the CA emissions and EPA emissions. The CA emissions system had three catalytic converters and four O2 sensors. The two extra cats were directly under the exhaust manifold and are often referred to as "pre-cats." To accommodate these extra cats, the exhaust manifold is different on the 2000 and 2001 from prior years, with two outlets instead of one.

The EPA version didn't have the pre-cats. It had only one cat in the normal location under the passenger side, and it only had two O2 sensors like the '99 and earlier models. However, it used the same manifold as the CA version, with a twin downpipe in place of the pre-cats. The EPA version is more desirable but still limits your choices.

The result of this design is that it's not as easy to find cheap headers that will bolt on. The ubiquitous APN junk found on eBay will not fit. You can modify the EPA exhaust to use the earlier headers if you want, but you're pretty much stuck with the pre-cats in the CA version. The good news is that there are some decent headers available for these years, but you end up paying a bit more for them.

Also, because the stock exhaust configuration is expecting the low pinion front axle, if you swap in a high pinion axle without a lift you may have an issue with your front drive shaft banging into the down pipe. I suspect most people who swap in a HP D30 are already lifted or lift it at the same time, but if not you might have a problem.

Having been through the 0331 head saga myself and having made some terrible mistakes along the way, I would still be willing to buy another 2000 if the price were right. However, I would do things a little differently, depending on how I expected to use it. If it were my only transportation and I wanted to make sure the thing was bulletproof, I would just plan to swap in a Clearwater head to take care of it on my timeline and avoid the issue altogether. That way I could have confidence that it wasn't going to decide to crack at a really bad time. I might not go to that expense if I had other reliable transportation available, but even then I would be watching the head like a hawk for any sign of cracking, and I would be sending out my oil samples for analysis at every oil change to catch any warning signs.

 

I knew that..

Seems like some good info right there!

 

My 2000 XJ stripped the distributorless timing gear at 170,000 mi. and I replaced the radiator at 172,000 mi. But those are maintenance items -- admittedly and hopefully not frequently. Otherwise the perfect vehicle.
You could pull the distributorless timing gear for a peek but that's heavy going. If you trust the records and the price is right, go for it.