RE: Questions about modding an Enforcer...
The problem besides being too thick is the weight of the plane must cause it to fly with more AoA than the same sized deltas that are designed for max speed.
Before the Diamond Dust came out, this style delta was all I used to see at the field and they were all much slower than you would expect. If they were built within weight limits they flew OK.
I imagine it would take a turbine to get one of these planes to really move out.
For all the work that is involved, I'd rather base the design on a Screamin' Demon then go from there with a custom center section to accomodate a rear engine.
I would tuck the engine into the aft end as far forward as possible
I got tired of dealing with engine heat issues and gave up on pushers as possible speed projects.