Chassis Tips

The chassis or frame is what is underneath the car, the floor pan etc.

Cables - hand brake, brake lines

These can give great effects, wowing your friends by having some cables under your models, just be sure to use thin wires of different colour (paint as needed)

Making leaf springs

These can be made from plastic strips, cut lengths and glue together to create desired width, curve clamping as you go.

Coil springs

You can use springs from things like ballpoint pens for springs for rear ends (diffs) or even front springs, springs from lighters can be used for throttle return springs etc

Exhausts

Can be made from anything, but using solder gives a more realistic effect and is easy to shape

Mufflers

Again can be easy, using a larger solder for round mufflers or cobies is one way, another is to use tin foil or similar to make oval mufflers. Only problem with tin foil is it's really to shinny, but I guess there is nothing to say you can't have chrome mufflers.

Nuts and bolts

This is probably one of the most overlooked things in detailing, every car, truck, bus, plane, train has nuts and bolts exposed, but we'll keep this to cars. The engine has bolts, the chassis has bolts, the cross member has bolts etc etc. To make these bolts you could dab a bit of paint to give the appearance of bolts. Or you could get a smallish piece of aluminium and sand the side to a hexagon or similar shape then carefully slice off small sections and glue these to your models as bolt heads etc