a little bit of oil in the cooler is ok, some people flush them with water and then use like a brake clean or degreaser in water to flush it, I just drained it and let it sit for a few days so it could drain out, as I didn't want water in my intercooler.
Hicas lock bar is quite east to install on an R33 as you only need to unplug the rear steering rack, unlike the R32 or Silvia where it was hydraulic. But if you are looking at getting a few things done suspension wise then it wouldn't be too much to have it installed as they would need to remove the old steering rack anyways. As for brands and people to do the suspension work, talk to fulcrum at Moorooka, they have done lots of R33s.