The new tires worked much better than the stockers, in some cases too well.  I eventually removed all the weight from the rear wheels as once the rears grabbed the rig would just rotated around the rear axle. I also tried cutting every other lug from the front tires and the rig climbed even better.

Due to their taller size the rig was feeling a little underpowered so I upgraded the motor/speed controller with a Novak Mongoose brushless motor. "Fast" would not be a word used in any sentence describing a stock MRC but with the brushless setup you can jump stuff if you wanted to! Of course all that torque forced a center gear upgrade after stripping the stock plastic unit. This is definitely a mod that makes the MRC closer to a real crawler that has horsepower in that now you can actually use momentum to get up an obstacle modulating the throttle as required to get the tires to grab. Now I try to finesse it first, if that fails there is always plan "B" - bump it!. Another cool side effect is you can now turn sharper by punching the throttle at full lock, just make sure you have enough weight in the front tires.....

Of course now Cameron's rig didn't climb as well so we ordered him some Losi Rock Bashers which were made from a softer than stock rubber compound.  I glued the new tires to my old stock rims and weighted the fronts with stick on weights.  To our amazement he immediately started making obstacles and climbs that my rig would not despite the stock suspension!  The flatirons had much better ground clearance but the big lugs were not as effective as the small lugs on his Rock Bashers.

Not to be outdone I picked up a second set of tires and rims: some HB Rovers and some Axial 1.9 bead locks.

As you can see the rovers are a lot smaller than the Flatirons and a hair bigger than stock (the Rovers are compressed a bit due to the wheel weights). The Rock Bashers are actually the smallest of the bunch (far right).

Since stick on weights would not fit in the Axial rims I coiled solder around the rim and held it in place using a layer of electrical tape. One spool of solder is a half a pound so it is cheap and easy.  I also thought the wheels seemed better balanced than the ones with the stick on lead weights.

What a difference those tires made!  Both directional control and grip we greatly improved.

We now had to reconfig the verticals on our rock course to make them steeper as we could crawl everything that we had to hit with speed with the stock tires.

I next went back and 4 linked Cameron's rig in the back which really helps cut down on the torque twist in these chassis. His rear links were made from some hollow delrin and 3mm set screws I picked up from Rcbros.

Here's where I drilled the hole for the new upper links, I utilize 2mm hardware to re-use the stock rod ends.

 As a preventative measure I upgraded the drives hafts on both of our crawlers (I did eventually destroy a stock set on mine). The Integy aluminum drive shafts I chose have not been very impressive, we broke one the first run out and I had to go back thru all of them and loctite the set screws along with covering the cross pins with heat shrink tubing to maintain them if the set screws come loose. I ordered some steel drive shafts as a backup and am running one on the back of Cameron's rig (picture on right) with no problems.

 Since I no longer ran electronic s on my rear axle I moved my rear 4 link plate over to Cameron's rig and picked up one of the new RCbros plates.  It is clean and simple design. As far as shocks, Cameron is still running stockers. I went back to the stock shocks in the rear with some 3/16" limiters inside of them. I had bought a set of Hot Racing aluminum threaded shocks but between the leaking and lack of adjustability I would not recommend them. I say lack of adjustability because you'll usually want to drop the car but with those shocks and springs the lowest you can go is nearly stock height and the only adjustment is raising the car. It seems like internally limiting the sock travel internally just works better. 

One thing I will recommend is a set of Dynamite hex drivers.  The tips are made from drill rod so they are very hard and resist getting rounded off unlike about every other allen wrench I have tried.  The 1.5mm hexes on the driveshaft set screws are the worst to deal and I actually had to dremel one off after rounding off the set screw. these tools made them a breeze to remove. Also pick up a good 00 philips head screwdriver to handle the tiny screws in the differentials.

So there's one of the reasons I haven't finished my HR2 chassis :0  Seriously these things are a lot of fun and addictive!