Yea, the 8XL is a good choice as well. The 7XL is fine up to 6S LiPo, in all honesty, but thats gonna take a pretty strong ESC and some damn good batteries.

I'm about to place an order for all of this, the esc is already on its way, now I am going for the 9XL, MM ESC, and CC BEC, also I am springing for the RCM heat sink clamp, or is that really needed?

My question is, should I go for the RCM
http://www.rc-monster.com/proddetail...WAND_XL&cat=20

Or is this what I am looking for:
http://www.offshoreelectrics.com/pro...prod=fei-540XL

I am confused between "xl" and "XL", I don't want to drop some money and have the wrong motor show up.

Also, is the RCM heat sink clamp needed, or is there a mod I can do to keep the can on?

Can I run 5S on the MM, or should I stick with/ be fine with 4S?

I am running a 46 tooth spur on the truck, what pinion should I run for racing and what for speed? I am needing a pinion that fits the Feigao/Wanderer shaft.

Thanks for all of the help again, pics will be up when the truck is done, which I am trying by mid January.

You'll want the 5mm bore mod1 pinions. The hardened ones can be used with a steel spur. http://www.rc-monster.com/proddetail...1pinion&cat=40
I think 14-16 is around what you'll want for racing, depending on temps.

http://www.rc-monster.com/forum/showthread.php?t=6832 Don't know if you've seen this thread, but he's using a very similar setup to what you'll be using. He does have extra capacitors on the mm which he says help keep the temps down.

I don't know how common it is for the motors to come apart, but it does happen. I've seen people use long screws and a plate to clamp the motor together, but it won't have the heatsink. You were going to do long races with it weren't you? The feigao will probably need heatsinks for long races.

The xl and XL will be the same thing.

Some people had luck using the older mm's on 5s, but it seems the newer ones are a bit different and don't work above 4s or 12 cells nimh.

I wouldn't go for the 9XL like bl_rvo suggested. Go with a 7 or 8XL for sure. Using the KV times the voltage, aim for around 35,000 RPMs. The 9XL will only be in the 20,000 range I believe. Trust me, the 7XL is a great motor on 4S.

Lots of peeps run the 9XL in buggies and truggies. It's all about gearing and voltage. He could run any of the 3 motors and have a good setup. I've heard of quite a few 7XLs going out after not too long, not to say they're bad, but I believe they're meant for lighter and smaller vehicles. A 8XL or 9XL is ideal for a heavier, 1/8 scale, and more power-hungry machine.

Not to mention a 7XL is going to burn more energy trying to take off, as well as require a lower gearing since it doesn't have the torque a 8XL or 9XL would have. If this was a Nitro MT or some other 1/10 scale truck, it would be fine. However, he has to be able to push the truck easily and without heating issues. In my opinion, he needs a 9XL to be happy and get good runtime as well as the proper torque. Gearing can make up for the loss on the top end and he will still come out on the cool side of Feigaos.

Quite of a few people start out with a 7 or 8XL, only to upgrade to a 9XL later due to heat and torque complications.