Hi Ixion,
Take a look here:http://www.rcgroups.com/forums/showthread.php?t=1065830&highlight=arpro
The boat in stock form is already very quick, I managed to flip it in the first 50 yards on the maiden run...
Like all "RTR", you'll need to unbolt everything that can be unbolted and 'rebuild'the boat with loctite for all screws and sealant on all through hull parts.
After you've gone through the plastic props, which are rather fragile, alter the shaft, by shortening it on the motorside, so you can run standard Graupner K-series props.
You'll be amazed at the increase in speed.
Depending on how high the shaft exits the transom, you'll be able to fit props up to 45 mm (2318.45K).
The stock 1520KV outrunner is very economical and gives you long runtimes.
As you can see in the topic in the link, I've made 'some' changes to the boat to make it race legal, the best addition is the floodchamber, as the boat floats disturbingly stable upside down...
Make sure to tape the hatch, as it's not really watertight and do check the fake exaustpipes on the lid, mine were open, causing the boat to fill with water rapidly after a flip.
Let me know if you need more information.
The much smaller Offshore Warrior is an entire different story; docile on 2S and virtually uncontrollable on 3S, not quite my cup of tea, I like the smooth sailing og the Arpro better.
Regards, Jan.