O.K. Gang,
Thanks for all the info and comments. For the last few months I have been reading and lurking as I read and researched information on XK8s. After watching ads and internet commercials, yesterday I finally went shopping and after a couple of stops, a few negotiations, I finally wrote a check and am now the proud owner of a 2006 XK8 convertible that is sharing the garage with my 2017 F-Type. Now I just have to persuade my bride that she really does need that extra Jag in the garage.....
It seems to be in excellent condition(don't they all in the first few days), but is missing the primary(black) key. Dealer says I must go to friendly neighborhood Jag dealer to get replacement(?). Also missing tonneau cover. 1 owner car according to CarFax with 49,000 mi. and condition seems to support this. Paint and interior is in excellent condition. It is a gold colour that appears to be original with tan interior. All buttons and dials work. It even came with a Barry Manilo CD. One of the CDs in the cartridge did give an error. I do not know if that was temp or not. Will have to check.
Oh well, today is the check out the rest of the car day. I checked all the major items during the initial buy shakedown yesterday, and the 1 hr. drive home. Now I can start asking some realistic question from all the knowledgeable people here on the forum.

 

How involved with this car are you planning to be? Vanilla answer is to go to the dealer and get a new key with transponder, get it cut, and then added to the car (programming). That will likely set you back several hundred $. And this is just for the key, the fob is extra.

Other option is to contact a local locksmith service. They typically come to you, but also expect high $ for the service.

Other option is to work towards a newer style flip key: diy-flip-key-conversion-without-reprogramming-guide-pictures

You can find the fob (or a pair) on eBay for pretty cheap. You will also have to source Megamos 48 transponders (cheap, too, on eBay). There is also an eBay vendor that cuts keys based on a picture of an existing key ($35 each). Last part is to pair these transponders to the car. Vanilla answer is the dealer (say, an hour labor), but some code scanners (Foxwell, etc.) can do this too. The idea is that if you are going to be involved in the repairs to this car, you will likely want to have a Jaguar code reader anyway, so buying it now is a good idea. It will likely pay for itself over time...

Best of luck, keep us posted.

 

The quick answer is 'all the above'. I plan to do as much work on the car as I am equipped to do. There was a time when I changed brakes, clutch, carb, head caskets,etc. Now, about 25-30 yrs and 30 lbs. later, I prefer to contribute to the local economy, and do the things I can do in my garage, beside my wife's Cadillac SUV, and my F-Type, with out chancing adding to my local MD's bank account. I have a good local mech whom I trust to handle any heavy lifting, but I call the shots.
The car came with a transponder for locking doors and unlocking trunk, doors etc. I hope to just get black key cut. Is the dealer the only option, or are there other sources? Flip key would work if not too expensive.

 

Well, the remote/fob to lock/unlock is readily available and can be made to work with the car by following a series of simple steps. There is no special tool involved.

In order to prevent starting the car by hot wiring, the car security system requires a successful crypto protocol with a transponder device built into the key handle, about the size of a big grain of rice. The exact type is Megamos 48. So, yes it is possible to have a key cut that can operate the mechanical locks (doors, trunk), but that alone cannot get the car started. To get the car started, the transponder chip needs to be present AND paired with the car by following a software procedure on a proper scan tool. The dealer/factory software can do this, as well as a number of readily available scan tools.

On another note, have you tried to reach out to the prior owner for any keys left behind? On a one owner car, this is likely to work out. Separately, if the seller only gave you a green (valet) key, you can try and guilt them into giving you a full key or at least pay for part of a new key. Your only key should not be a valet key...