If you get this error: Unregistrable node: cars\racers\Toyota_XE10.rpk:0000A0E5 (invalid parent parts.rpk:0000B282)
It means the exhaust pipe is in a catalog which MWM does not have, How to fix it:

Convert the RPK of the car to RDB
The name of the RPK is Toyota_XE10 [For me] So you have to Right-Click on the Resdecode.bat file, press edit and put in the name of the RPK file
Link to restools

Now you should have a rbd file
Open it with notepad, Press CNTRL + F And search for B282 If it doesn't find anything search for: 0DB4 , 0CB4 , 0EB4 , 00B4 or 0AB4
When you have found the exhaust type ID

Simply put 0250 There instead of B282 [or any of the other ID's]

Now convert it back to RPK with the Resconvert.bat file

It should be working fine now

[Made this for the people that don't like/Don't use LE2MWM]