i'll be bolting it in and trying it out before i attempt to remove and fix or replace the standard tank, it's a very common thing to do on a lot of modded cars and i've never heard anyone say it didn't have a good outcome.
On my way back from France i had around 20 litres of water (some drinking, some for the engine), 5 litres of oil, a litre of brake fluid, 5 litres of antifreeze, least 25kgs of tools and spares including a trolly jack, large hammer etc etc, a spare wheel in the well and enough clothes, food and stuff to see me and my brother through the week. Let's just say the car had way over what's considered normal in the boot. All the weight was above and behind the rear axle, the worst possible place for it. On the way back my bro decided to tell the sat nav to "avoid all tolls" which i didn't know about so ended up making a wrong turn making me very mad in the process. I drove like an absolute loon from that point as it was now very late and not once did the tail want to come out, unless i wanted it to and it was very progressive when it did. The weight in these cars are biased towards the front anyway and with the 200lb springs and uprated shocks / polybushes it seemed to take the weight very well. I'll do it anyway and let you guys know how it goes. I cannot imagine it will make any noticeable difference to handling, if anything i can see it improving.
The gauntlet hath been lain and the bets are on[:D]