here the rules for trail class Julio- sounds like mod class is pretty much unlimited, what sux is that your rig don't fit in the stock or mod class for ultra4 either, maybe they will grant you an exception of some sort since all your missing from being a stock sami is the rear sheet metal.
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Stock Trail
1. Frame must be stock full frame (exception, when bobbing the rear then only can a minimum amount of frame be removed, equal to the amount of body removed), with all cross members (exception, frt. Cross member with changing to a straight axle).
2. Suspension type must remain the same as OE, per vehicle production year, make and model.
3. Any axle up-grade is ex-acceptable
4. No tire greater than 37" by sidewall listing or metric equivalent
5. Full body vehicles only, bobbing is allowed between rear axle and rear bumper, but at least 24" must remain from centerline of axle to rear of bumper, no dovetailing or boat siding allowed
6. No cutting of floor is allowed with the following exemptions. The center section of the floor is approved for cutting & rising to allow drive train clearance directly over drive train components. This does not include Drivelines, axles or axle shafts. Cutting and re-boxing for the clearance of non-suspension items, including tires, shocks and fuel tank is permitted. No boxing for clearance of springs, air-shocks, or suspension links is allowed.
Modified Trail
1. Must have body panels including hood when starting the race
2. Any suspension mod's allowed
3. Stock or round tube chassis's are acceptable
Both Classes
1. No By-pass type shocks allowed, in mod trial coil-over shocks are acceptable
2. 6 point cage of acceptable design and configuration, must be at least 1.5" .120 wall or greater and magnetic steel material
3. Minimum of 4 point harnesses must be used for both driver and co-driver; they must be in good shape and show no signs of wear or weather damage, condition to be decided by a Dirt riot "Official"
4. Side protection/Door bars required
5. Minimum 6000lb front mounted winch wit synthetic winch line, winch must be operational
6. Solid roof required, magnetic metal of at least .040 or aluminum of 1/8" in thickness acceptable
7. Complete floorboard and firewall required, firewall must extend from inner side panel to opposite inner side panel, and from floorboard to engine hood.
8. Fuel cell/gas tank must be separated from passenger compartment. Fuel cells must be strapped and not flange mounted
9. Minimum 2 5lb fire extinguishers must be mounted within reach rescue personnel, and mounted in such a way as they are secure but easily accessed when needed.
10. Seats must be mounted securely to the cage or floorboards
11. All Wiring, brake lines, fuel lines and vent lines must be in good condition and secured as needed
12. Battery must be of a dry cell or gel cell construction and securely mounted with a cage, box, or over the top strap.
13. Rear facing amber light must be visible to rear approaching vehicles; light must be hard wired so it stays on with ignition switched on
14. Vehicles must be equipped with differential locking devices in both front and rear axles
15. It is highly recommended that vehicles be equipped with beadlock wheels
16. Vehicles must carry a small first aid kit
17. Driver and Co-pilot must wear helmets, helmets must be dot, SNELL or FIA approved. Helmets must be current in dating and in good condition.
18. High back seats or helmet pads must be used
19. Neck support devices are highly recommended
20. 1 piece fire suits and shoes are highly recommended
21. Window nets are highly recommended
,,,, so my "ECORS" spec built, A-Class race car would NOT be in the "Dirt Riot version of A-Class" ,,, 
