Hi guys! What effects would be impossed on the car if a) there was no rebound instead of 100% rebound and b) if the diffs were run hi instead if low?

Maybe it's coincidence, but I tend to try and build with 30-50% rebound anyway, which probably achieves what you're saying.
I hardly ever have to rebuild as well.

They say that the higher the grip, the less rebound you should use, but it really seems to depend on the track and whether it has any bumps etc as well.

Can't recall on the diff's, have you checked the manual

On the topic of rebound - Per Paully "The Deader the Better." Yes there are exceptions, but this is the general rule.

I always think of the diff height as an influencer of on-power and braking fore/aft weight transfer, although there may be other explanations as to its effect. My reasoning to this is that the moments about the car's CG due to the belt tensions during power and braking effect the cars attitude, or at least its fore/aft weight transfer. Nevertheless, to me the changes are hard to notice on the track, at least in blinky 17.5.

Raise the front diff height: more on-power rear weight xfer (i.e. more squat), less dive under braking.

Lower the front diff height: opposite of above.

Raise the rear diff height: less rear squat on-power, more dive under braking.

Lower the rear diff height: opposite of above.

Seems to me a shock would be more consistent thru its travel (wile raceing) just a few mm +- the static ride height.
I mean if shock is built using 8mm shaft exposed . But has no foam and has hold drilled in cap would it not push inand stay within a few mm of that area? Only think iI think would be trying to push it out would be the pressure on the Blatter. Where as if u build shock to 0mm when ur car is setting at ride height or racing on the track the blatter is always sucked down (pulling a vacuum) and would eventually draw air into it self

What u think Christian T ?lol when u going g to get some X-ray parts in stock ?
I'm waiting g to order once ur springs and spool cups come back in stock

Just tried fitting pinions with the kit spur (84t, 48dp).

Trying to get at the pinion set screw with the motor in it's position is a pain in the ar$e, the hole underneath, just like the T3'12 in central, trouble is, now the motor is more central, so is the pinion. It's teeth are right above the hole.

So far I have removed the motor and put the pinion on, once the edge of the pinions I use (RW Racing) is flush with the face of the pinion shaft I know it will line up perfectly.

On the plus side;
Using the new mount I managed to get a 35t pinion (4.56fdr) down to a 15t (10.64fdr) before the motor started fouling on the layshaft mount. It's on the limit of access to the motor screws though

If the pinion is flipped, you can tighten it with the handle of the hex driver on the front shock tower.

HAs anyone thought of a way to protect the bottom of the chassis? I run on a large outdoor trach with kerbs that are curved but about 1.5-2 inches higher that the road. With my sakura every time i went over one it would scrach the frp chassis pretty bad.
Is there abyting i could put on the bottom of the chassis to help lessen the scratches that may or may not damage the carbon chassis of the t4?

Clear adhesive shelf liner? If you can't find that, even duct tape will work in a pinch, but it will leave residue behind when you remove it.

I usually have a piece of cell tape down each side of the car underneath.

You'll get the odd scratch in the middle, but most chassis damage seems to be near the edges, particularly near the motor.

Waiting on the new toy to show up....

One thing I've been told about is a clear film that can be bought which is usually used as a headlight protector. It is clear so you can still see the carbon fibre if that is real important to you and it is designed to absorb impact.

I'm yet to try, but I might for the T4 which is due next week.