My overhaul

Right, before I go any further I have a disclaimer. I'm a novice enthusiast. I don't know much about the work but I'm willing to get as much knowledge and experience to see my landy through the years it deserves.

So I'm going to do three bits of work within this year. Obviously I want the best of the best kit going into it but I'm not able to afford that, she'll kill me having that said I don't want to be stingy if it's going to last me a good few years. If there's any details I can add that would help on recommendations just let me know. For the basics it's a discovery td5 series 2 GS. 160K miles, diesel 5 seater.



And lastly is two options ECU or a decat pipe for exhaust change out.
Now I've heard the ECU is a bit of a dark art so I'll leave the programming to a professional but if there's anything I can do to prepare the vehicle that would be great.
As for the exhaust well it's showing signs of rust so I think a nice change out will benefit all round.

Thanks in advance and if you're in Edinburgh drop me a message. I'd love to meet and see things you other engine heads have done.

Regarding "kit", buy the tools you need when you need them, a good start is a decent socket set which includes some Torx bits. Buy the best you can afford, not necessarily the best that's available, especially if you're a DIY mechanic.

Brakes
The pads should be considered as "service items" which should be checked and replaced as necessary. Don't wait until all the friction material has vanished. The discs are easy to replace and don't cost a vast amount.

Suspension and lifting.
Before you go any further with that particular subject, Take a look at this thread, particularly the entries by @300bhp/ton.

https://www.landyzone.co.uk/land-rover/lifting-a-d2-properly.300573/#post-3749057

Depending on the set up of your vehicle would depend on how you treat the suspension. If you're on air then treat the air bags as service items and expect them to last about 5 years, give or take.
I wouldn't be changing my springs just because I like the colour, there's more to it than that.

The ECU
Yes, reprogramming that can take a certain amount of expertise, and the right kit. You'd be best off getting used to the vehicle first then asking about getting a remap done later. A number of things you can do before you go down that route such as removing the Exhaust Gas Recurculator (EGR), cleaning out the intercooler if it's found to be necessary, inspecting and if required replacing the air pipes between the turbo, intercooler and the inlet manifold.
It might be good idea to check the inside of the red plug on the ECU for oil contamination. If there is any present them it's going to mean a replacement injector harness.

If you want or need to go into the electrics and electronics on the Disco 2, you will need a compatible code reader, don't be tempted by the cheaper ones on the net, in most cases they're a waste of money. Your best bet there might be to make friends with somebody local to you who has access to the right kit.

Learning as you go isn't always easy, so some technical help is always useful, don't rely on the Haynes "Big book of lies and half truths", download a free copy of RAVE from:-

http://www.myrangerover.co.uk/rave-workshop-manual/

Apart from all that, maybe your first jobs should be a service; all the oils and filters and check the condition of the auxiliary drive belt.
Oh, and I'm not likely to get to Edinburgh, the closest I'm ever likely to get to Hadrian's Wall is York, and then only once a year.

As @brian47 says, full fluids and filters service first, buy good quality tools and just enjoy driving it first.

Chassis rust will be your greatest enemy so go over it meticulously and see what it's like and make a note of any rusty and crusty bits that will need attention in the near future.

You should either invest in a good code reader or find a local friend who has one that can help you out.

This is the LZIR rescue and help map https://www.landyzone.co.uk/land-rover/the-lzir-map.264099/ have a look and see who is close by that you can mutually arrange a hook up to see if anything is up or to help when something does go square shaped.