Never had an issue with CVAs popping out so not sure. Make sure you get the right one for the B4.1. With the B4 and T4 the Diff bearing in the transmission were 3/8x5/8 (I think) and with the B4.1, T4.1 and SC10 they moved to a 10mmx16mm bearing which would require new transmission case.

http://miponline.com/store/mip09130.html

What batteries do you guys prefer in your 17.5? I'm running nanotech 4200 shorty packs and they're great for the first couple minutes but they seem like they lose a lot of punch pretty quickly. I run nanotechs in my scte as well but I don't notice the loss in punch as much because the truck has so much power. However with 17.5, I obviously need every drop of power I can get especially at my track. I understand all lipos will lose some punch while using them but like I said, mine seem to be losing quite a bit of punch. Do you think it's just because they're nanotechs or does this sound normal? Btw, they're only about a month old and they're very well balanced. No puffing or anything.

I have had the same problem with my shorty reedy packs

that's the one I had linked too. I'm 99% sure he said that part number.
will call and make sure before I drive there.
but I have the RTR with dog bones. not CVA's. so I'm hoping I don't need the CVA's also.
I don't want to keep upgrading this thing. I'd rather move up to the 4.2 factory team instead.
I just upgrade parts as they break. the gear diff for whatever reason stripped out on one side so I want the ball diff. I don't even want the good shocks. this is my learning the ropes vehicle.

The rtr dog bones will pop out if you don't put orings in the out drives and in the axle ends

I run thunder power shorties, lots of punch!

Same here. You get what you pay for.

we ended up running 3 o rings in the out drives just to make sure on our rtr.

Is it a must to run a short in the 17.5's? I run the 13.5 and was going to move my new 4.2 to 13.5 and the 4.1 will be my 17.5. Was giong to run the carbon orion 90c lipo in the 17 since I have two. I don't have any shorties. I like the trinity double duece shorty but like orion and have good luck so far with them.

I would try

http://www.teamorion.com/carbon-pro-...-90c-7-4v.html

Added the Shock tower mod to the first page. This is Bill's mod he used to move the tower forward to better mount the BB shocks.

question on the first page gearings, 13.5 reedy brushless, 22 pinion with 81 spur. I am running a 29 / 72. Being a newbie quite a bit a difference in FDR, what are the pros and cons?

I actually spent today swapping between shorty and full packs, reedy 3800 vs reedy 6500. The full pack felt a good bit faster, and more consistent through the run as expected. I ended up running the same laptimes either way though, and the weight difference felt like everyone has described before, heavier a bit more stable, etc etc.

That gearing was based on using boost.

My car has a bit too much initial, not enough mid and plenty of exit steering, what should I be looking to change?

I'd try the standard stuff first.. or change your driving style a little. Add a limiter in the front shocks(internally), put the rear ballast weight back, go to a normal ride height(check setup sheets or start with 23-24 F/R) Good luck! Also look into going 1 step stiffer on springs F/R to green/white