as i said speak to Glyn on here, he has a 2.5 being pinned at the moment and knows far more on 2.5's than me - thats why ive stuck with a 2.0 sti to avoid any problems
know your cars far from standard but obviously theres a difference between strenghtening a healthy engine and repairing a damaged one - i believe agra in dundee would carry out the work your looking for, theyve built several engines for time attack. theres also api engines down south and roger clark motorsport