I got this Traxxas "Chaparral" Villain IV at the neighborhood garage sale for $30 about 10 years ago. In stock form, these boats are idiot-proof and very user-friendly, but quite heavy and rather slow.
I recently updated the electronics. I installed a new 2.4 GHz receiver to use with my Slash 4x4 trigger-style transmitter. This also allowed me to eliminate the external antenna used by the old 27 MHz radio. I also installed a Traxxas EVX2 speed controller, which is a 16v monster truck ESC designed to run two packs in series with two brushed motors. With its own on-board BEC, I was able to eliminate the 4 x AA battery holder to save some weight. I have a jumper on one battery connector, running the boat on a single 7.4v LiPo pack (Turnigy Nano-Tech 30c 5300 mAh.) The boat is now feather weight, reaches its top speed within 2 seconds, still takes huge waves no problem, maneuvers quickly and tightly like a mouse on crack, is nearly impossible to flip or swamp, and runs forever on one pack. The stock motors get nice and hot, but the new ESC barely even gets warm.
In the future, I may update the stock props and shafts with metal props for a little more ooooMPH.