I own a 1998 XJR X308 4.0 V8 Supercharged. Recently repurchased it after owner blew head gasket. Have motor torn down and heads ready to be milled. I would enjoy hearing from anyone who has experienced this. I would like to upgrade fuel injectors,coils, plugs and am looking for a suggestion there as well as any performance upgrades anyone has successful experience with. Any tips or sugestions would be appreciated

 

Plenty of threads such as this one... https://www.jaguarforums.com/forum/x...pe-more-75812/ ...do searches, with ported supercharger, 92mm MAF, ported heads, rebuilt heads.
Right off, the best way to upgrade the fuel injectors is to send them off for cleaning. There is a company in Houston, TX that does it and again, a search will bring that up. The specced iridium plugs are the best you can get for this app. I'm sure some more folks will provide more info.