Actually doing a full tune-up on a '03 X-Type 3.0 I bought at auction. Plugs, coils, top and bottom intake gaskets since I do need to change valve cover gaskets, among other things. While I have this top side apart to the cylinder heads, is there anything else I should go ahead and do while I am there? I am new to Jaguars and new to X-Types so not sure of the "institutional knowledge" as it were.

 

Yes, plugs and coils. Make sure you purchase quality European coils and good plugs.

 

imho the best possible plugs are: Denso IT20TT. That is twin tip technology & iridium. They last way longer and provide the perfect spark.

Re: cam-cover gaskets: Do not forget to apply RTV as well, especially at the few spots, where it is expected. I had to apply a bit more - all around on the underside of the gaskets for some reason, else it would still leak. Observe the max torque on the air-intake bolts: 10Nm - I would not go much higher than that.