I have been a bit worried about that, although the smog pump was disconnected and the vacuum advance inoperative the last time it was smogged and it passed both the visual inspection and the sniffer test. The tech opened the hood, muttered something derogatory about British cars and proceeded to check off all of the visual inspection items without giving it a second glance. Getting rid of that damn POS Lucas alternator will be worth the hassle though, that thing was always causing some charging problem and was impossible to get to without crawling under the car.
The other visual differences under the hood are the late model V12 fuel rails and Delphi disc injectors, electric fan setup, Taylor ignition wires and the ignition vacuum advance components being moved from underneath the intake manifold where they were getting baked. The only thing currently not working is the smog pump, but I have a newer electric-driven one off of an XJ6 I'm going to mount underneath the alternator and hook back up. The next time it's up for smog everything should be hooked up where it's supposed to be, so I'm hoping the tech will also not want to dig too far into it.
The new injectors appear to have improved throttle response and allow me to run the thing really lean at cruise without surging (around 16:1 is what I can push it to when playing with it, with the old injectors it was unhappy even at 14.7:1.) Fuel economy is about the same though, as is WOT performance. It does start more easily though, the saturated coil injectors pull less power and run cooler, and there's far less rubber in the fuel system now. There are some lousy cell-phone camera images of the install here:
http://crosstalk.atomz.com/~ross/jagstu ... r_install/