While at a junk yard I looked over a couple of 99 range Rovers both of which had tubular headers. The engines were 4.6 Bosch's
My question is will the headers fit/work in a '03 D2 ? How much modifying would it take to make it work?

 

I'm assuming you mean the shorty headers that came on them from the factory.

They'll bolt onto the heads and if I had to guess I'd say they'll clear everything, but they won't bolt up to the exhaust.

What's your intent in swapping? If its power gains, don't bother. The difference would be negligible. If you're going to go through the effort of doing headers then go all the way for long tubes.

 

217 hp vs 225 hp, right?

 

Not exactly sure what the numbers are, but I know the P38 also got a little more timing advance which was supposed to give it a touch more power. At least that's what I've been told.

 

Spark advance and cam/valve advance or just one of those 2?

 

Spark advance I believe. And actually, from what I've heard you can swap the ECU from the Bosch powered P38s.

 

Neat tip!