Hey guys,

Might be sending my 03' XJR down to buckhead imports so they can fabricate a set of headers and possibly other performance mods. Anyone interested in a group buy? These guys are the real deal and they do phenominal work. WHO WANTS TO GO FAST!?!?!

 

When the time comes I'll get my own set made up.
Most after market companies are a joke and don't understand how to group up the cylinders of a V8.
The Jaguar AJV8 requires that you group up cylinders assymetrically bank to bank- grouping up cylinders that fire 270 degrees apart. In addition it must be of a large enough section to accomodate the gas flow of the particular application.
I' ascertained that 4-into 1 per bank is less than ideal for our engines.
If you want an example take a look at the Aston Martin V8 Vantage exhaust manifolding and how I grouped up the manifolding there.
If the grouping can't be made as above- then I'd simply go for a log manifold with exceptional sizing (on the supercharged variants). This is not the best as on the SC variants this log (in addition to the intercooler design) leads to a severe imbalance of Air to fuel ratio and volumetric efficiency per cylinder.
One day I'd love to address this...

 

Not anywhere near the detail of the Count's post but FWIW, I've never had a set of aftermarket headers that had any durability.

If you do go ahead with the headers, make sure they use high quality stainless tube.

 

On another note. Would love to see photos of your car. Sounds nice.