I don't know what all the hype is all about but there were nothing special about them other than the engine thats it. I worked on these cars at the dealer back then and I can tell you they had problems when new. Yes it was faster than other G body's but not the most attractive one and especially the granny speedometer and the small led tach and boost gauge that you can barely see when it was sunny out thats just my opinion. Driven the GNX when new it was faster than the GN and i liked the way it launched from a dig but going over bumps it felt like you were in a dump truck because of its rear suspension but its more of a quarter mile car and deserves respect . My son asked my one day how come i didnt buy a 1987 GN, my answer i was happy with my 85 442 and they way it looked but if i needed more power for the street i took out my 71 super bee 440 six pack and had fun. GNX will always be top dog since it was a limited edition. CK80 is correct there were other cars that are faster, you could walk into a chevy dealer and order a 1987 callaway corvette RPO B2K
The engine is exactly what the hype was all about.
C4 Vette is a piss poor vehicle, regardless of modifications.