You may get one on here as i believe someone was selling one from Holland where he is based although im sure he was scottish i'd imagine its sold now but they do come up. Im not an expert but im not 100% sure of the benefits of 5e unless u are forging it. you could run that kind of power on a 4e and would save time effort and money. You can easily get 220-230 reliably from a TD04 set up. Cost wise if you have then engine as standard for the turbo kit and brain id say around the £1k mark. I couldn't help with the gearbox questions although i doubt they made an LSD for the 85 as they didnt have the power to justify it. Suspension id imagine is totally down to yourself are coilovers suitable for rally or are you better with a spring and shocker set up due to the punishment they will take to allow for a cheap replacement.