On this thread, page 81 post #2007, shows the jet with the N20's
and the Defender props installed. Post #2023, shows a close up
of the N20.

If you want to fly it, and it will fly good, remove the back piece you
installed, leave the bipe motors in it and replace that lipo with one
from the original AA bipe or jet.
AAMods has em for about $8. You should be all set.

Or get a pair of N20's with the larger props and that will solve your
power problems with the heavier lipo.