Yep, WIM can fit your ARBs if you want. Or most places really, it's not a big job.
The drop link thing is pretty much luck, as Aido said. My car had done just over 50K (and was 9 years old) and two out of the four drop links were seized and needed cutting off. The problem you may find is that you go to get them fitted, then if any of them are seized and need replacing you obviously need to get hold of the parts. What I did was buy four new drop links from Lexus/Toyota and I checked that they were happy for me to return them for a refund if I didn't use them (and if I didn't open the packets). In the end I decided to use them all, drop links are something that wear out in time anyway, so since I was putting a couple of new drop links on through necessity I thought I'd go for the whole hog.
Back to one of your earlier questions, I had my car WIM'd before doing the ARBs. But when I went back to WIM yesterday (due to suspecting I had knocked the geo out through a slight mishap), Tony thought that my new ARBs had indeed affected the geo slightly via the increased stiffness (not greatly, but affected nonetheless).
Regarding the Cuscos, I was slightly concerned (when I was looking around and trying to decide) that unlike most of the uprated ARBs, the fronts have an even greater increased stiffness compared to the rears, so it might alter the handling characteristics (oversteer vs understeer etc) rather than just making things flatter when cornering. I thought it seemed like the C-Ones would be better. Also I didn't find anyone who actually had the Cuscos and could therefore comment on what they were like. I'm not trying to say that the Cuscos are a "bad" choice, just explaining why I went for the C-Ones.