Cunningham VS KLEIN ?
They both inspired each other at different times and besides that Gary Klein and Charlie Cunningham had some common innovative ground for Aluminum frames - yet also broadly different approaches. One being more an artist and constant innovator! The other more of a salesman and designer. At one point even the bigger tried to eat and cheat on the smaller with lawsuit. Nonetheless for the few hundred Cunninghams there were only some painted and in modest shades, where as to the thousands of Kleins many were sprayed in the most artistic colors/techniques (what is not rare has to look rare to sell as rare Cunninghams were bare or better said bred as the purest conception of the perfect simplistic offroad transportation/transformation machines..
But where i should have started, Charlie was inspired to build his Bikes and soon the very first Aluminum MTB when he was looking to buy a road bike. He thought he could do better than what he saw with Klein´s racing bikes yet aknowlading what was being inspiring and popularly received of a novel idea from the roadside of things.

Restomod´s ?
Over time some of Charlies bikes from trusted owners as well some of Cunninghams personal riders got heavily updated with well working parts. So in the truest sense to improve a machine with well working additions.

Fervor Frame Duo,
In fact the Nebula color scheme was the early design for introducing the Fervor line and seemingly nebula red was one of the rarest nebst sprinkle blue, silver and especially green being the more common factory paint choice ..
Then what is it ? well its like a pinkish Candy Red with black sprinkles, a slightly more appealing effect compared to the other inverse Nebulas. The described pattern was officially only available from 93 to 94, by 95 (KLEINs last pre TREK year), the Fervor had received a plain metallic color finish..

Top.G. -> Rascal -> Fervor
These bikes are build up for maximum fun/performance and not in need to be period correct,.. In fact you might wanna still call it NeoRetro
.. that said, original forks are stashed and to be kept for the day needed !

The Fervor frame originating from the 1989 introduced "topgun" and later called "rascal" models. These are basically all the same in structure (never mind paint ) & total solid race frames... as they have longer toptubes and no rack mounting options by comparison with a Pinnacle. Besides mentioned less decorative elaborate paintjobs of the more expensive models, wall-thickness and butting helped to make these basemodels less prone the braking around areas of headtube joining´s when heavily raced against say Attitudes and Adroits!

Yet in smallest and medium size as displayed here, there are nice ways to adapt to the choices of how different they can be set up.

typical Klein measures here:
small frame is an XS 18"
medium frame is M 20"

Sidenote,
Charlie hates the plastic taste from typical bike bottles so he acutally made cages to hold glass (!) bottles
Hence my little Homage with the bare Aluminum ringle cage and his type of rubber-make-fit-perfect notion