Nic,
what I use as a base colour is 70% Tamiya XF-60 "Dark Yellow" and 30% of " XF-2 "Flat White" thinned at 50% with 90 vols rubbing alcohol (ispropylic).
The exaust, with a bit of practice, is easy to be done:
a) cut a section of copper tubing of the desired diameter to the length, file it if the edges are a bit rough and hold it in a vise
b) with a soldering gun put a bit solder around the edges of the tubing
c) cut two squares (rectangles) of copper foil exceeding the diameter of the tubing of roughtly 1mm and put some solder on one of the sides
d) position the copper square with the soldered side towards the tubing edge and heat it with the soldering gun until the solder melts and grants the adhesion between the foil square and the tubing section
e) repeat the operation turning upside downd the tubing and soldering the other copper foil square to it as done before
f) once you're done with that trim out the excess of foil and file/sand it down to shape
g) cut an other lenght of copper tubing (this will the terminal part of the exhaust) of appropriate diameter and gently "squash" it using a pair of pliers and file/sand the edges if they're rough
i) with the soldering gun apply a bit of solder on one side of the "squashed" tubing and solder it to the cylinder you obtained before
k) cut four discs out of pasticard (sheel or rod) that will give you the supports to glue the exaust to the tank on one side and the exaust "shield" on the other and glue them in place with CA
j) cut a rectangle of copper foil and shape it around a tube a couple of millimeters bigger than the one you used for the exhaust body. Cut it to match (1/2 mm longer than the width of the exhaust with the four supports glued).
l) now cut a lenght of plastic/copper tube, slice it at half to be glued on the top of the exhaust shield and finish with milliput or another epoxy putty to give it a rounded shape
m) finish with the appropriate rivets
Gosh! It takes far a lot more to be exlained than doing two or three of them...
I hope this can help
Ciao