Hi, I'm new to this so unsure I'm sure if I am posting correctly! I am looking to buy an XJ40 very soon, my 6th Jag, and I want to do a few tasteful mods to it. Can anyone recommend a company where I will be able to get an exhaust system and lowering kit? Nothing too over the top, I just want to give it a nice sound and firm up the handling. Thanks, Dan.

 

lowering it won't firm up your handling... installing a thicker sway bar and ensuring all your bushes are in good order (pay particular attention to the steering rack mount bushes, ball joints and tie rod ends) or changing out the OEM rubber ones for poly will. Although keep in mind that firmer bushes will cause excessive vibration which will lead to problems with the electrics over time.

As for the exhaust system, have a look here... http://www.jagweb.com/aj6eng/exhaust3.php

 

I've come to learn over the years that building your own exhaust is far more cost effective and allows you to tailor it to your desire. I plan on running a magnaflow muffler setup without cats as I prefer a louder tone. Under $400 is easy to do.
Bushings, don't believe the hype. Poly bushings aren't remotely harsh if you buy quality. The higher the durometer, the stiffer. Powerflex does Jaguar bushings in 85a and 105a and really don't cause excess NVH.