Your idea isn't good
. Drop-it ! Most of people there,use their coupe like everyday car...So,if they said 2854 si useless option..trust them;)
My 2860rs runs with absolutely NO problem,on stock internals engine for about 4 YEARS and about 60 dragraces...Full boost at about 3000rpm...almost like the (very poor) stock turbo ..isn't enought for you? If is not,stick to the tb28(std) turbo;). That 54mm compressor is good for offroad truck or for Fiat Uno turbo tuned for ..shopping:D..No offence mate !