The part load breather pipe for XK8 is part # AJ8-4880 and for XKR is AJ8-4879.
As far as I can tell, the only difference (other than price!) is the XKR version has a length of vacuum hose and some heat wrap tape over a section of the two hoses.
The actual part load breather pipe with the tee fitting into the throttle body and the fitting for the cam cover breather and evap end look the same.
Can anyone confirm the actual part load breather pipe is the same? It would cost much less to purchase the XK8 part , some vacuum hose and heat tape than the XKR part...
Thanks!

 

HC:
Just my 2 cents. I recently did this hack. I think it was Motorcarman that suggested that unless one is removing the supercharger, just do a temporary hack. Being in the business, he has seen plenty, probably even similar to mine.
Note: I used my smoke machine ( 11 inches of water or less than 1/2 psi air pressure in the system without smoke) to listen for any air leaks in the new joints with a stethoscope / rubber hose as even a small leak may set a P0171 / P0174 code.
Also, it seems like some have performed the surgery of OEM replacement without removing the supercharger. Maybe someone else will reply.

 

You can also, quite literally, just take any rubber hose of the correct diameter and slip it on both ends of the system (valve cover and intake tube?) and use a small clamp on each end and tighten it only pinky finger tight to not damage the plastic connections. It will cost a lot less and will probably have an acceptable lifespan. If you don't mind a non-oem look, this should be easier than trying to mend the original part or hack the XK8 part.

Also, rubber is a lot harder to break than brittle plastic when you are wrenching on the car.

 

Take a look at the parts on SNG Barratt's website. You will find that the normal aspirated part load breather hose 17 inches and the supercharged is 25 inches long. My guess is they won't interchange.

 

Aha! Interesting...
I had a crack in the corrugated pipe at the tee fitting, I repaired it with adhesive lined shrink wrap but I suspect more of the plastic line will fail.
I like the "hack" , but as this is a vacuum hose I would think it important to use vacuum line (hoses designed for pressure can cavitate under vacuum) and no one around here carries any larger that 1/4". I shall do some searching.
I did recently use fuel hose to replace the coolant lines to & fro the throttle body & EGR valve, as that is the only hose I could find to fit locally and the little factory hoses are crazy $$ and don't even fit that well. I have not had any problems with them, but I will source some proper heater hose soon and replace with that.

 

Good point: Cavitation can happen. my 1/4" Tygon coupler (see attachment) imploded over about 2 years. Currently, I am using 3/8" fuel line hose. (My 1970 Firebird brake booster hose was fuel line from the factory and actually had "GAS" printed on it)

 

I can make new breather pipes for the 2003 thru 2006 XKs with the 4.2L engine.

See my contact info on my XK8 bible.