I prefer the speed and handling of cats and like to live life on the edge so a little less stability in the wind doesn't bother me. If it is an issue to you get the Tenshock Mono1 as it is the only self-righting RTR close to your budget.
Plenty of info on the boat mini_t racer linked in this thread
on RRR &
OSE
I built the boat above and it cost me:-
$100 for the kit
$130 hardware.
$199 1412/1y is the motor I wanted but Nue wont let you order direct and it was taking castle so long the Emailed me asking if I wanted to cancel and I had a line on a used 1415/1.5D so ended up paying $120 for that motor.
all the rest of it was bought here in the UK or used from my stores so aproximate dollar prices for new replacements from here on.
$45 Skywing 200A ESC
$15 thermal epoxy to watercool the above air ESC
$5 alloy tube to watercool the above air ESC.
$5 electronic grade silicone sealant to waterproof the above ESC, RX and Servo.
£100-200 4s battery pack, last 2 seasons I went for the cheap end, this year I will be getting an expensive TP pack.
$60 servo.
$10 6mm bullets.
$5 bottle of medium cyno.
$15 30 min epoxy.
$30 epoxy laminating resin to seal the wood.
$40 paint, paint is optional as the laminating resin makes it waterproof and the natural wood does look pretty good, I used primer 2 colours and clear which all adds up.
$10 stanley/craft knife.
$10 emery paper.
$5 grease for cable.
$5 oil for motor bearings.
$200 Futaba 6EX radio/$65 for RX/free as I had it already, depending on your viewpoint.
Prop, sky is the limit here $7 for graupner carbon props that dont need balancing, 10-20 for BeCu or stainless metal props if you can sharpen and balance them yourself, $20 for a good magnetic balancer, $30-70 if you need someone else to do it for you, or $1000+ for a box full of props built up over the years like I have.
The one on the right hand side is my 1415 rigger.
I may as well answer you PM here so all can see, i favor the AQ MC to the PB Impulse Purely de to my own bias towards cats and personal preference, there is nothing wrong with either for the stock power, it is just like me prefering buggies to monster trucks, and F1 to Nascar.
The PB impulse and AQ MC both have very similar power systems and as such will give similar run times, as nitrostarter said dont expect anything like the run time of your cars/trucks though, if i pull ovals with my onroad buggy i get peaks of 120A but the average ampdraw is only 20A my boats which are set up for Naviga hydro racing I pull an average of 70A with peaks of 120A 15 min runs with the buggy and 5 minute runs with the boat, and that is quite a soft setup compared to the states where sprint racing it the norm, for 5-6 laps and its all done in a minute and a half, if you are concerned with runtimes stay away from the big 1415/1515s and stick with the stock spec motors which will give you over 5 mins on the stock prop.
I moved on from RTRs before RTRs came along and as such I have had neither but I believe the Impulse 31 does have room for 4s2p but the AQ MC does not have room for 2p, 2p does not necessarily mean you can run twice as long though anyway as the extra heatsoak from that long runtime may be too much, those that race with 2p may be discharging less than 5000mAh in the minute or so that they are running for but need the 2p, to avoid large voltage drops on the high currents they pull and the weight to keep the boat on the water at the high speeds, while they may have the capacity to run for 3 minutes if they actually ran that long they would fry the motor or ESC.