These are smoke systems for your Extra.
There are 3 colors, Red, White, and Blue.
First, put the effects in the main Flight Simulator Effects folder.
If you want Red, put these lines in the Aircraft.cfg file:

[SMOKESYSTEM]
smoke.0=0.00, -0.70, 1.40, fx_smoke_r

If you want white, put these lines in the Aircraft.cfg file:

[SMOKESYSTEM]
smoke.0=0.00, -0.70, 1.40, fx_smoke_w

If you want Blue, put these lines in the Aircraft.cfg file:

[SMOKESYSTEM]
smoke.0=0.00, -0.70, 1.40, fx_smoke_b

If you ever want to change the colors, just change the last letter of the line.

For example, if you have red, and you want blue, change the "r" to "b".
Red-r
White-w
Blue-b

Here's what it would look like:
Before:
[SMOKESYSTEM]
smoke.0=0.00, -0.70, 1.40, fx_smoke_r  

After:
[SMOKESYSTEM]
smoke.0=0.00, -0.70, 1.40, fx_smoke_b

The Extra is already equipped with the white smoke.

Easy as that! Have fun.