The front bulkhead / gearbox is a very similar story to the rear, with two large alloy ‘sides’ to the assembly.  The rear most suspension mounts at the front end are added to the chassis at this point, this – unlike the rear – is split into two parts either side of the front gearbox.  The mounts sit inside cutouts in the chassis and are screwed in via three counter sunk screws from below – giving a really solid anchor for the front suspension.

The steering assembly sits within the front belt loop and consists of a twin bell crank design.  The parts are all moulded plastic and there is no servo saver built in – though one is provided on the servo horn.
The bell cranks ride on twin ball races each side and the steering link is also endowed with two more ball races and  steel bushings. When all clamped together the steering is virtually slop free and buttery smooth. 

The front top deck does a similar job as the rear’s – tying the front and centre bulkheads together.  This top deck needs two body mounts attaching firstly, but with the under-tray and some Velcro (included) to attach the shell, it’s probably not really 100% necessary to use these mounts.

The 501X uses CVD style drive shafts with long front bones and short front axles, and vice versa on the rear.  The shafts are marked with their length in MM to avoid confusion – though to be honest the shafts are vastly different lengths so there should be no mistaking them.
Some of Tamiyas excellent Anti-Wear grease is supplied with this stage and should do a good job of extending the life of the joints.

These CVD shafts are manufactured opposite to how MIP manufactures theirs. The axles are also drilled twice for the CVD pins, so when one set of holes eventually wears the axle can be rotated 90degrees and the next set of holes used. 

The suspension arms front and rear are likely to be familiar looking to many people as they are very similar to those seen on the JConcepts BJ4x4 (front and rear) and Associated B4 (rear).  Looking at the rear arms, the design and length are as close as they can be to the Associated items, with an extra hole for the shock mounting and the anti-roll (sway) bar mount on the opposite side of the arm.

The fronts are similarly derived from the JConcepts car with similar overall dimensions and look, though certainly much beefier and thicker.  The major incompatibility is of course the metric / imperial size difference with mounting hardware - so parts can't be readily exchanged between cars here.

The rear hubs install with a captured hinge pin – the screws used in capturing these outboard hinge pins are a tad large and require a bit of force to install – perhaps Tamiya just wanted to make sure.

The rear wishbones push into place at the rear of the car and the rear suspension mount / toe-in brace holds things together.  The toe-in brace is yet another nugget of blue aluminium and can be shimmed downward to give more anti-squat.  No shims gives Zero anti-squat and one shim is recommended in the manual.

With the rear brace screwed down from below - you get massively strong, very smooth and free mount for the wishbones - which is totally slop-free and should remain so for a long time. Impressive.