What does adding an XF throttle body achieve? I have an n/a vl calais and after some easy mods, have already got extractors and air pod/filter. Any help appreciated...

Stuff all unless you have a bigger plenum chamber to make use of it.

please explain in more detail....what kind of plenum chamber would I need if i got an xf throttle body? and where do you get them from (plenum chambers)

..XF throttle body is larger than the VL one, if the VL throttle body is a restriction in the intake than the XF one can help. But if you have a stock induction set-up your throttle body most probably isnt the restriction in the system. Its not worth doing unless your current throttle body is a restriction - with your mods I doubt its worth it as you will need to modify your plenum for it to fit or get an aftermarket/custom one made.

thanks guys.....but it seems there are other plans for my car...like the junk yard, driving home in peak hour and some one forgot to use their brakes....luckily no one was hurt, just the car she's a write off. Cheers anyway

Sorry to hear about your car dude.