Some potential engine choices beyond the XG40 if for some reason the money to continue with XG40 isn't found:
[To compare EJ200 is 13,500lbf dry/ 20,200lbf reheat]:
RB.199-34R
8,530lbf dry/ 15,300lbf reheat
RB.199-42R
9,700lbf dry/ 17,000lbf reheat
RB.199-52R
9,220lbf dry/ 14,810lbf reheat
RB.231-02
10,900lbf dry/ 15,600lbf reheat
RB.168-89R
Spey development, 12,210lbf dry/ 20,430lbf reheat
RB.409-50R
RB.199 development. Considered for modified Tornado to meet AST.403, 8,770lbf dry/ 15,475lbf reheat
RB.409-70R
RB.199 development
RB.431-10R
Straight-through Pegasus turbofan, 15,850lbf dry/ 28,030lbf reheat.
The only plausible choices would look to be maybe RB.168-89R but that's probably aging and fuel consumption would be higher, or possibly RB.431-101R but that might be too large to fit two into EAP. I think on balance in an ideal AU I'd stick with XG40.
