Alternative to Bowden extruder (4 replies)

Hi Guys
I am the process of building the Smartrapcore printer with square Aluminum ( 19.07mm ) tube.
I was wonder if anyone is using a Greg's wade extruder with their Smartrapcore because I read that Flexible filament does not do well with the Bowden extruder ?

I would appreciate your advice and which extruder I can use.

Thanks
Vaughan