would be kinda unnecessary. You wouldnt need this product unless you were drifting your car, or had a shit tone of power. And when I say shit tone I mean 700+.
It would come in handy if you were drifting, because there is a slight chance than when you had the car sideways for an extended period of time that one of the cylinders could get starved of oil. This product would engage in that case and probably save your engine of a costly ceaze.
Actually, the celica, especially the GTS, will die of oil starvation in right hand turns, if you are going fast enough. this is because all the oil sloshes away from the pick-up end of the pan.
Autocrossers should definitely install one of these; that way, when there's a drop in oil pressure, the accumulator will kick in and dump it's supply of oil into the system. Oil can then reach the pickup. once the oil pressure rises again, the extra oil returns to the accumulator for it's next duty cycle.
Trust me, many GTS owners learned this th hard way when on their first autocross session, they screw up the engine.
These can also be used to pre-lube the engine before starting it, which will increase it's longevity big-time
A baffled oil pan will also prevent the oil starvation problem, but comparing features, and the fact that the brash boy oil pan is seriously overpriced, an accumulator would definitely do the trick.
Morosso makes some nice, inexspensive acumulators.