They are not bad cars, always liked look of them, engines good, brakes truely aweful, drivetrain so so, interior remains same as normal Sunny. The buying guide Jamie refers to was in Pratical Performace Mag i think, which of course last year a GTiR won the £999 challenge where you bought & prepared a car for under a grand then drag raced it, slamon tested etc
I have a brilliant car mag from 1992 which road tests it against its other homologated rivals, Lancia integrale, Escort Cosworth, over 6 pages, it was outclassed in handling, driver feedback, involvment, cross country pace etc but recorded the quickest 0-60 time on the day, though was qucikly overtaken by both other cars and recorded slowest 1/4mile time IIRC. Which sums up its returns in WRC where famously the intercooler was called interwarmer where cars got slower as stages went on due to heat soak, much to Nissan's dismay at not reading the rules of the day correctly and therfore not knowing that they could not move the intercooler from top of the engine to a more advantageous position.
I think best thing with them is keep them pretty much standardish or mildly modified upto 250ish bhp, upgrade the brakes and fit nice wheels as the standard 14" wheels, hence shocking brakes fitted inside did it no favours, and you will have a car that rewards as well as behaves itself.
I think only 70 UK Sunny's were ever brought in, these will be much cheaper to insure as with all Jap imports they attach a premium.
I love all the homologated cars from this era though, integrale's, GT4's (OK had to say those 1st as have them both), impreza's, Mazda 323 Turbo, BMW E30 M3 (yes it was used on hard surface rallies with some success) Mitsi EVO's, Cosworths, GTiR's just seemed more exciting than it is now because you could buy a road going car built to be able to race.
Good luck if going that route though remember runing a 2L 4WD Turbo car is not going to be same as running a 1.3 Turbo FWD car.