You guys are missing the point
$5 for a fully upgraded JR7-F is an excellent deal. Hell $5 is a fine deal for the 300xl alone, regardless of the fact that everyone has one. Time being money and all, handing over a fiver is much much cheaper than grinding for the engine, even with a premium time/hero mech stack... which many folk have no problem just moving engines around, but once your mechbay reaches a untenable size, constantly tracking down engines is a chore.
And if you want something else, you can shuck the wee bit of cash and flip that Jenner for some quick C-bills at a much better rate than the c-bill package pricing.
And now, everyone flood redundant posts detailing how foolish it is to spend real money on things you can get for c-bills in this game because none of us have heard that detailed before.