Short answer, You may get away w/ your plan locally and be stopped driving in another county or another state.
Long answer,
If you think factory lights are "dim" now, HL mounted very low won't light as design and perform worse. Is part of why Fiero hidden HL are the way they are. Is enough height to work and when open the bulbs are close to or = to same height in most other cars. (If the HL are yellow or dim then bulbs are likely old or wrong bulb used or very likely have major wiring problems in the car. See my Cave,
Headlights )
Fiero Front Park/Turn bulb works w/ Front Side Marker. Just switching either/both to LED causes problems to many. Worse many including most vendors say need "load" resistors to work but the resistors
eats more power then OE bulbs do. If the resistors are mounted poorly then you hope only the resistor(s) fry off. Power resistors heat can wreck other things. (Fiero and many other AC/Heat blower resistors can burn down your car. Use search to find examples and why.)
See my Cave,
LED Marker Light and
LED poisoningMany states have Min and Max height allowed for HL and Many cops see a easy ticket on any "HL" mounted at or below bumper level because can say fog/driving lights on w/o Low Beam HL. Many areas have more rules like fog/driving light only in bad weather and LB HL on. (In some states "Equipment Violations" for iffy mods, dim/dead lights, and so on may have Points too and can follow you home cause home state and insurance problems. Worse if you still have other Points at home.)
Badly mod'ed park/turn/stop lights can be a ticket magnet too. Even crap LED sets from China etc wired wrong so bright side is on w/ park on and dim side for turn light can fail inspections or get you stopped. So Don't trust Ebay Amazon and Many other vendor claiming LED are "DOT approved" or = to 1157, 2057, 2357. First is almost always BS and bulb numbers may fit but many LEDs are wired "backwards" to them. Even when an aftermarket light fixture from a big name like Trucklite is "DOT approved," many are for different jobs and are labeled as such.
Labeled? see
Lighbulbs at bottom.
------------------
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