Removing 1 or a few AC parts won't store more. Even Fiero w/o AC and sunroof options barely stores two 1 gallon bottles.
Roof storage shelf just hinds heater and brake booster.
Front area isn't meant to store anything other then spare and jack.
All Front space is part of Fiero Crush Zone. Anything put in there can be problems during or after a wreck and why the tire and jack is "bolted down." Youtube shows Fiero crash testing...
You + passenger + Loading w/ whatever often creates problems because Very Easy to Overload a Fiero.
That Problem, At Minimum, Eats more Fuel and takes more Driver Effort to Stop. Even then can take Longer to Stop.
Fiero GVWR is setup to include two 190lb people and ~ 100lb cargo. (Most other cars GVWR is ~ 190lb adult per seat + ~ 100lb Cargo unless NHTSA recently change that formula and that only cars build under new rules.)
You can safety change What is carried
but not Total Weight of the mix.Some remove spare tires and get "Fix a Flat" types instead... But most don't know FaF only works in a very small set of flat tire cases and often won't work in cold weather. Many Tire Stores will not repair a FaF tire, only replace them. If you have paid "Hazard Insurance" for the tires, that may Void the contract.
Related note: Many Fiero have truck "luggage" rack but mainly use only for light bulky stuff to get somewhere local.
Having things there can mess up air flow thru the engine vents even if doesn't cover them cooking many parts.
Rack load points won't take a lot to pull thru the lid as is, more so when wrecked anywhere on the car. IOW Heavy objects attach to this can turn Ballistic very easy.
Cops mostly don't stop overloaded/overweight cars but after a wreck can have huge problems w/ Insurance and more.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave