First of all Civic EG came from the year 1992-95, from 96 Civic EK took it over as a successor.
-The build quality is brilliant and if you get hands on a Ferio (JDM variant), it'd be more fun and treat to drive as compared to the PKDM. Comfort level is so far so good, Suspension (Double wishbone) is well known allover the world, most of the suspension parts are interchangeable with EK/DC Chassis, you can get them from the Junkyard as well as brand new, everything is available like Bearings, Ball Joints, Shocks, Hubs, Bushings, Axles etc. Braking is good too and the JDM ones even came with 4 Wheel Disc setups and even PKDM ones can be upgraded.
-Stock Carby is not bad at all but only if you find it in proper running condition which is hard now a days cuz its almost a two decade old platform but that's not going to be an issue cuz a lot of swap possibilities are there.
-Parts and Maintenance per year? Well this totally depends upon the type of use-age and all. If a car is running on all eight, it wont require much of a maintenance apart from regular oil intervals, filters etc. A ruined car will require costly maintenance again n again. Parts are not cheap when compared to Suzuki Margalla. You can get Headlamps, Tails, Corner Lights easily and in a fair price too, but when it comes to such parts like Weather strips, Front Moldings, Hood, Fenders or Doors, they are expensive, but one can get brand new taiwan made body parts too in a fair price but they wont be that much reliable as compared to Oem parts. However, one can't easily find the optional rare goodies which were offered in this specific model.
-Civic EG only came as Civic Ex in Pakistan, a lot of other variants are available for the rest of the world including SiR, EX, EL, VTi, RTSi, MX, I dont know!
-Swapping the stock caby with an EFi is not an issue, very easy and friendly to work with. EFi D Series will be your best bet which is not going to require any changes apart from the wiring, even the stock gearbox (S20/40 i believe) will work flawless.
-Aftermarket suspension i.e Coilovers, Strut bars and Sway bars are a very good upgrade but that must be at the end of your list, try to get the other things in working state first.
EGs has got a lot of potential but it all depends how much you put in and in which way. All the best with your hunt.