So, specific recommendations
1: Use the Kelvin's impulse texturing where the two 'gaps' are on the aft of the ship, on either side of the central fin. This most pointedly keeps our espionage thing going without having the Cruiser.
2: Encompass the impulse stacks with something so they're not exposed. We're not at the D'Deridex level, so some housing is needed. Again, I would look to the Kelvin style secondary hull plating for cues for this.
3: Kelvin/Enterprise hybrid warp nacelles. They're not M/AM engines, so they don't get all the way to the cool stuff, but they should look a little more 'modern' than the cigars. This will likely be the piece that harkens to the Cruiser the most.
4: Use something akin to the Kelvin's bridge dome for the boom's bride. Doesn't have to be a direct lift, again, but it should hint that some of this bird's technology isn't exactly native.
5: Lastly, in the same vein, use Kelvin-style emplacements along the front ventral and dorsal of the secondary hull for it's 'phaser banks'.
Optionally: Add some mass to the boom, like an 'ECM rail', maybe glowing, to show the guts of the Plasma Launcher, if you're inclined to use it. (Maybe even have a visible conduit leading to the impulse generation housing cowls.)