alot of the bushes in the 1800 are cobbled from other models in the mitsu range!
lower arms are the same as a colt, some of the rear bushes are the same as the fto and evo, if memory serves one of the anti roll bars are e6 bushes etc etc
my one and only recommendation for getting bushes would be camskill
www.camskill.co.uk, they list alot of parts for the 1800 now and alot came about from bushes etc i got for mine so should give you a starting point! you will want to speak to mike and give him your chassis code and a list of bushes and he will do the rest!