That's correct, at the beginning i had the inrunner, then the outrunner. I've already sold my CRT.5, but if i look back, i think i would take the inrunner.
The outrunner setup is nice and you can save a lot of weight, but it didn't like that you can't change the gearing. With a new Outrunner it's really great and powerful, but when I had about 50 runs on it, i could feel that the power is decreasing. Outrunners aren't made for offroad use, they don't like the small stones and all the dust. I did the outrunner conversion because nobody had done it before and i love trying out and finding new solutions. The outrunner setup is funny but if you want something that is easy to use for over 100 runs without any problem, then take the inrunner.

Currently I have my CRT.5 converted using a SpeedPassion 7.5R with 11 tooth pinion using only 2SLipo. The conversion is easy and clean. However, I didnt really like the noise from the metal-to-metal gears.

Thus when I researched on other alternatives, i found this site and the idea of using outrunner motors. From your video, the car seems so smooth and noiseless. I really like it!

However, the place I play RC cars is actually a gravel field.... so maybe outrunner is not a good idea. (unless I built a stone-proof housing around the outrunner... but it may get really hot!)

Anyway, thanks for you comments.

Reaserch the plastic spur mod.

yeah, i read about the Kyosho plastic gear. in fact, i have 1 right now, but because i will run the car in a gravel field, the plastic gear will be chewed up in no time.

i still find the outrunner option a very 'cool' setting, since it is direct drive which provides lots of torque and is ultra-quiet.

You are completly right, it's smooth, light-weight, quiet and powerful but not very durable under real offroad conditions. It's not to expensive, if you've already got a ESC and a battery you have to spend around 50$ for the motor and some small parts like cups, dogbones and a motor mount. If it works stable under the conditions of your driving spot, you can keep and have a lot of fun. If you've got problems with it, you don't have lost too much and you can use your inrunner again.
The Kyosho gear is quite durable, i don't think it will be damaged.

If you are worried about dirt and dust getting in the motor, use some kind of foam or screen on the holes of the outrunner. It will still provide cooling and keep the rocks out. I say try the kyosho plastic gear and if that gets chewed up and you feel an outrunner is your only option to quiet it down, go for it.