Side Repeaters

Changing them is easy.   Simply take off the existing covers - then carefully rotate the inner mounting until the lugs which locate it in the wing can be withdrawn through the cut out notches that are there for that purpose. Now - the new repeaters are unlikely to need any of the old mountings, which means cutting the wires and attaching them to the new kit.

You may find that the new fittings need modifying in order to get a good snug fit -
don't be tempted to start hacking around with the hole in the wing to do this, take
the time to slowly take off just the amount of plastic needed to get a good tight fit.
That way the new repeaters will be supported properly, and not with just the sealant
you use to weatherproof the joint.

Another tip when you've finished - use some tape over them for as long as it
takes the sealant to cure, you may put them in and think they're not going to move,
only to find next day that they've gradually shifted and set in place at an angle,
meaning you'll have to pull them off, remove all the sealant, and do it again.
 

Colour Coding

The most golden rule when spraying is preparation, closely followed by the correct
conditions - follow these two rules before you spray and you're well on the way to getting
a good looking job done.
 

Don't be lazy and attempt to spray bits whilst still on the car - You won't be able
          to prep them properly unless you take them off.

Always use a primer coat - grey or white depending on the final colour you're aiming
          for. If the bit you're spraying isn't metal, use a plastic primer,
which can flex when dry.

Always spray in mild to warm conditions, ideally just after a good shower, which
          takes all the dust and bugs out of the air for a while - if you've got a garage, damp
          the floor down first. Don't even try spraying if the temp is less than 10 degrees C -
          you might end up with a horrible milky effect where the solvent in the paint did not
          evaporate fast enough.

Get the piece smooth, then clean it thoroughly with a detergent solution, then wash
          off with just water - let it dry naturally, or if you can't wait,
use a lint free cloth to wipe dry.

Sand the final coat of primer and wash again before applying the actual colour coat

Now it's basically down to how good you are with a spray can. Basically, don't try and put
too much on - gloss paints and laquers etc. will run very easily - much more so than primers,
so don't go wild and try to get a final finish first try.
Also, let the coats have a chance to dry a bit before the next one goes on.
 

Delocking
Delocking is a good way to achieve that subtle smooth look, not to mention extra security.
The best way is to weld in a piece of steel plate - screwdrivers can still be punched through
if you just use an extra piece of standard panel thickness steel. If that's to much trouble,
you can get a little insert with a threaded stud on which is held firmly onto the old lock
hole by a nut and large steel washer behind the door skin - you could even smooth the hole
with filler afterwards to achieve the same smooth look, or at least paint the insert body colour
to give the same impression  - at least at first glance.

If you weld, careful not to warp the door skin with heat - use spot welds all the way round,
          alternating to give the heat an adequate chance to dissipate.

Make sure you give yourself an alternative entry in case the central locking packs up or
          your battery goes flat - I would recommend leaving the tailgate lock on manual opening.