The original version was the now-discontinued and ready-to-run Savage 21 which served as the basis for the vehicles that came after. It featured a unique boxed chassis with parallel aluminum panels surrounding the transmission and drive axles, two-speed transmission, heavy-duty slipper clutch, eight oil-filled coilover shock absorbers, four-wheel-drive, HPI .21ci (3.4cc) pull-start engine with rear exhaust and an HPI 27 MHz three-channel pistol grip radio. A "reverse module," sold separately, mounts inside the transmission where it replaces an idler gear assembly. It utilizes the factory-installed radio's non-proportional third channel and an additional servo to add the convenience and fun of reverse when the model is first brought to a complete stop.
Shortly after the Savage 21 was released, the Savage SS was released. It was an unassembled version of the Savage 21.
The Savage 21 was replaced by the updated Savage 25. This version added both a larger HPI .25ci (4.1cc) engine for additional power and torque as well as HPI's unique "Roto-Start" electric starter system. The Roto-Start kept the weight-saving advantages of the pull start with the extra added convenience of electric starting via an external electric starter. This starter, standard on most new HPI models, incorporates a gear-driven one-way bearing mounted on the engine in lieu of the pull starter. The external starter is a motor-driven gearbox which spins a hexagonal steel shaft and is powered by a standard 7.2v nickel cadmium battery pack. A pinned ball joint at the end of the shaft mates with a socket on the rear of the engine-mounted one-way bearing assembly. The system has proven to be a popular one, with third-party engine manufacturers such as O.S. Engines and Team Orion designing their replacement engines to accept the assembly. An limited edition version of the Savage 25 added a three-speed transmission along with updated wheels and tires. These parts can easily be retrofitted to previous versions.
A mechanically identical (save for springs) variation of the Savage 25 replaces that model's Lexan pickup truck body with that of a Kawasaki KFX700 all-terrain vehicle with articulated rider figure designed to move with the model's steering motions. This model sold poorly, probably due to the effect of the expensive body on overall price and that it was still a Savage 25 when the Savage X was in production.
When the Savage 25 was released, the Savage 4.6 SS kit was updated to include the more powerful engine, improved differentials and other upgrades. A ready-to-run version, the Savage 25 Limited Edition, added colored shock absorber springs, a 3-speed transmission, and a commemorative bodyshell to differentiate it from the kit version.
An electric version, dubbed E-Savage, is a 1/10th scale version similar in design to the original. It is powered by two HPI "GT550" 14.4v electric motors and competes in the market defined by models such as the Traxxas E-Maxx and Kyosho Twin Force. It shares no parts at all with the full size Savage, due to the fact that it is simply a rebadged Hot Bodies E-Zilla. The next ready-to-run version was the Savage X. It had a new Force Engine-built 25 motor. The Savage X has addressed the criticisms of the original twin chassis design, which were poor radio box access and difficult access to the differentials. The enlarged radio box is now easier to open and the differentials can now be removed from the new "split bulkhead" design by removing only 6 screws. The new chassis plates lower the motor and transmission slightly to improve CG, and it now includes a standard composite roll bar and detachanble roll hoop to protect the engine. A variation, the Savage X SS, has a .28ci (4.6cc) engine that has 10% more displacement than the S-25 Model. The Savage X SS also features a hardened steel spur gear, chromed dog bones and 6 gear spider diffs for enhanced drivetrain durability to cope with the extra power of the .28 engine. With this engine the SS version will easily pull wheel stands and an optional wheelie bar is available for the Savage to prevent it from flipping over backwards under hard acceleration.
The overall setup of the Savage, with its massive tires and tall suspension, make it a poor choice for racing in stock form, but does enable the model to be able to withstand tremendous abuse. Racing Savages are not common, but HPI and other companies offer parts to make a Savage competent against other monster trucks.
Several hobbyists have had success using the Savage for high speed. The current RC monster truck world speed record is held by a Savage, at 61.9 MPH.
The original Savage SS 4.6 kit has been discontinued and has been replaced with a version updated with X equipment.
Also, one can now buy a Savage X SS kit without an engine, allowing hobbyists to install their own engine. The equivalent engine to the 4.6SS motor is the Axial .28 Spec 1s.
HPI Europe still offers the Savage 3.5 RTR. The 3.5 is basically a late model Savage 25 with the original Nitro Star S-21BB motor and two-element air filter. It also features new rims and blue chassis plates.
At the end of summer 2007, HPI released the Savage X 4.6 RTR. This model features the Force Engine-made F4.6 motor. The new F4.6 motor retains the reliability of HPI's motors while adding more power, though it is not as powerful as the K4.6. The driveline has been upgraded with new alloy differential cases, reversion to the more reliable 21/25-style slipper clutch, and a dual fiberglass brake disc kit. The clutchbell is now a 17 tooth unit.
The latest Savage, released in April 2008, is the Savage XL. This Savage includes a new K5.9 (.36) motor with aluminum tuned pipe and a stretched chassis. Several changes have been made to improve on the truck, including stronger diff gears, steel spur gear, uprated driveshafts, thicker chassis, metal geared steering servo, aluminum clutch shoes, 3-speed gearbox as stock, and much more. New wheels and tires and a new body complete the truck, which is RTR and comes with a rechargeable receiver pack and charger.