The Marsflyer is a one of a kind ship, that's for sure.
It was made by some of the best in the business. Harrier, Glock, Crabtree and myself.
Part of it is scripted but it has some custom files such as the sound the ship makes, custom weapons, custom manoverability, and a few other things.
So if you really want to add the Marsflyer you would have to add the necessary files including the cmp, mat, sur, marfly.ini add the custom lines from the beam_effects.ini and effects.ini engines, weapons, and on and on.
In other words you have to know what you're doing and it would take a lot of time even for someone that does know what they are doing.

You would be better off just using the Marsflyer mod in normal freelancer without any other mods.
You could ask SWAT_OP8R if he could include the Marsflyer in the next version of the Crossfire mod but then SWAT_OP8R would have to get permission from Harrier because he made the Freelancer model of the ship. All the other stuff you really don't need permission to use because I asked Glock and Crabtree to do what they did and I'm sure they wouldn't mind anyone using their work because it was done because I asked them to and I don't mind at all.

1. you cant add that ship to crossfire... you simply will be kicked out by the Crossfire cheat protection if you try

2. i dont really like to see the mars flyer in crossfire coz it does not fit into the mod

In his post I believe he says it's for use in Single Player with OpenSP.

Don't mind SWAT_OP8R he's actually a nice guy, he just works too much.
The Marsflyer is in the shop getting a new paint job.
When it's done it will be the coolest ship ever to terrorize Sirius.

it doesnt matter if its opensp or whatever
the new versions of crossfire block every try to manipulate the essential FL code... that means for MP, SP and OpenSP

we havent seen cheaters on our server for a very long time... and the best thing is... no additional serverload