Ok, firstly noone should be impressed with my results... I did what makes sense and it works. Plenty of people here in Aus have been running with anti-surge tanks long before me. So I don't take any kudos. The reality is I'm a bunny in this game.
Results? On my first couple of track outings, with good R-Spec tyres, any solid lateral g-force thru left handers and with the tank around 1/3 full, the pickup sucks air, which comes very quickly through the fuel line... and on exit from the corner (yeah, right when you plant the foot) the engine just stutters. In fact, mine emitted a couple of VERY loud bangs which scared the living shyte outta me.
Some of the more experienced track people here suggested that I wasn't driving hard enough, cause it SHOULD be happening at 1/2 tank (subsequently proven to be correct). Some of the harder core street drivers too suffered the condition.
So in went the tank (600ml) and Bosch external pump. I mounted both in the engine bay, while others have hung both under the rear compartment floor pan. At the last outing at the Island my last two laps of the day were with the empty-light hard on (minimum weight) and without a hint of hesitation through all corners a lot harder than I'd gone before.
The biggest difference is the peace of mind knowing that you're not gonna destroy the engine thru suddenly having little-2-no fuel at 6000rpm with the foot flat to the floor. Protection that lets you feel *more*? It does exist!
Second, if my factory in-tank pump was suffering, it is irrelevant now. All he's doing is low-pressure lifting to the anti-surge tank.
Third, better lap times.
Yeah, I'm not comfortable having the tank in the engine bay either, but it makes some sense to have the (new) primary pump right up near the rail.
As someone said, it depends on how you drive the car. Better handling/suspension will highlight the problem more as you'll go through corners faster.
peter