4 cylinder is the SDV10 or SXV10. 1995 was the changeover year. The body shapes remain the same and should share any aftermarket components between the SDV and SXV.
6 cylinder is the VCV10. The VCV10 also shares the same body shape and most components should be interchangeable.
The exact information can be found on the compliance plate at the rear of the engine bay on the firewall.
Not sure about the turbo, but the N/A version that I drove for work was terrible. About 450km per tank. Luckily it had a sub-tank, which pushed it to 700km for a total of 120L of fuel.
Coilovers are almost nonexistent for them. You may need to settle for lowered springs and shocks. Alternatively you could get custom ones made, but that isn't cheap by any means.