What is it? Is it beneficial to remove or do you lose reliability? Is it hard to remove?

 

Post vehicle information.

"Rats nest" generally refers to all of the emission equipment and vacuum routing under the intake manifold.

 

The rats nest does a variety of things. On an FD you'll get some serious problems if you just remove it all.

What year of car?

 

It's a 93. I don't have the car yet but I'm trading my car for it and the guynsaid it had a vacuum leak and I was told to investigate the rats nest

 

A vacuum leak that causes the engine to not idle correctly could be due to many things. The rats nest is only one of several possible places.

The other kind of vacuum leak is one that does not really affect idle but prevents the vacuum storage tank from providing vacuum to the solenoids. That issue causes stuff like boost problems. The rats nest is the place to look for this kind of vacuum leak.