RE: clunk line.
You can, and I always have on my planes, but I have found with the Raptor 50 the tank is so short that the line is too short to flex enough. All you need to do is make the clunk will touch all 4 sides of the tank. If it won't you'll need a more flexible line. I got some in tank fuel line for my R50 from Miniature Aircraft, the company that makes X-Cell helis. It 's very flxible and has worked very well so far.