For the regulations please visit the site
Or have a look into the attached document eetts_regulations.pdf

Summarized:

Rally-Cars

T1-Vehicles

(prototype cross-country vehicles) – Compatible with Art. 285 Appendix J ISC.; valid homologation for:

• - Roll-Cage
• - Seats & Seat-Belts
• - Tank
• - Race-Suites, Helmets & HANS
• - Visibly marked tow hooks at the front and rear
• - Emergency engine-stop from outside (both sides)
• - Fire extinguisher min. 4l
• - Fire extinguishing system is recommended (if existing: the fire extinguisher is unnecessary)
• - numberplate & green card
• - pilot and co-pilot have to have valid driving licences and valid racing licences

T2-Vehicles

(Series Production cross-country vehicles) Compatible with Art. 284 Appendix J ISC.; valid homologation for:

• - TBD

TH-Vehicles

are all 4x4/4x2-vehicles with roll-cage, with valid or expired (not longer than 5 years expired) homolgation for:

• - Seats & Seat-Belts
• - Race-Suites, Helmets & HANS
• - Visibly marked tow hooks at the front and rear
• - Emergency engine-stop from outside (both sides)
• - Fire extinguisher min. 4l
• - Fire extinguishing system is recommended (if existing: the fire extinguisher is unnecessary)
• - numberplate & green card
• - pilot and co-pilot have to have valid driving licences and valid racing licences

SSV & T3-Buggy-Vehicles

light weight vehicles without FIA homologation:

• - Race-Suites, Helmets & HANS with valid or expired homologation
• - Visibly marked tow hooks at the front and rear
• - Emergency engine-stop from outside (both sides)
• - Fire extinguisher min. 4l
• - numberplate & green card
• - pilot and co-pilot have to have valid driving licences and valid racing licences

RAID(HOBBY)-Cars

all OEM - 4x4 vehicles

with:

• - 1x Spare Tire
• - Fire extinguisher min. 2l
• - Helmets for pilot and co-pilot
• - numberplate & green card
• - pilot and co-pilot have to have valid driving licences and valid racing licences (in case of not having racing licence, you will become one-event - racing licence from organizator for 25€/person)

And there is another cool thing from orga:
Additional 20% Discount on All Categories for Only Female Pilot & CoPilot Registration
Additional 10% Discount on All Categories/Registration when Pilot or CoPilot is Female