HeadlightsAll headlights are not created equal and as the old adage says "you get what you pay for". So don't even waste your time or money on the $3-$7US sealed beam halogen lights you find at regular auto parts stores. They're not that much better than the ones that came with your car.
If you're willing to spend the money, E-Code headlights is a much better way to go. Theoretically, they are illegal in the USA except for off road use, but it is unlikely that you will get pulled over for using them. These lights are very white and even in their pattern. Unlike sealed beams, they are comprised of a separate lens and bulb. When the bulb goes out, you only replace the bulb. This means that the initial expense is high, but replacements shouldn't be. However, how often do you really have a headlight go out in the first place?
I replaced all four lights on my car after being disappointed with the sealed beam Sylvania ones and I can honestly say they're great. The only weird thing is that they have a very sharp horizontal cutoff that tapers up on the right hand side to help illuminate signs on the edge of the road without blinding oncoming traffic. Other than this, it's almost as if you're driving in daylight.
You could purchase your H1/H4 bulbs from Daniel Stern at Stern Lighting. Expect to pay about $40 - $65US per light for the E-Code units.
For the next step up in lighting beyond E-Code, you may want to go to H.I.D. (High Intensity Discharge) lights. These lights, also known as Xenon lights, have been in use for years in stadiums and factories. In recent years, they have emerged in the automotive scene and can be found on flagship vehicles from companies such as Mercedes Benz, Lexus, and BMW. The lights do not use a filament like a halogen bulb, but create light by zapping an arc between two electrodes. This arc excites gases which in turn ignite metallic salts producing an intense white light on the roadway. The results are impressive, consuming one-third the current draw of comparable halogen lighting while producing four times the light output.
H.I.D. headlights produce a color temperature of 4300 Kelvin versus 2800 Kelvin from a standard halogen bulb. For comparison, the earth's sun has a color value of 5200 Kelvin. Simply, the color temperature is a unit of measure of a light source. The higher the number the closer the light resembles actual sun light. This color spectrum ranges from dark red to orange, yellow, and finally white to light blue. This explains why vehicles equipped with H.I.D. headlights at night have a slight blue hue and halogen equipped vehicles have a yellow hue.
RM Lighting is one company that sells aftermarket HID that will fit the Esprit. For $995US you can buy a kit that includes 2 H.I.D. bulbs, reflectors, ballasts, igniters, H.I.D. bulb adapters, nylon mesh wire harness and relay assembly, weather pac connectors, plus 100W halogen high beams and all hardware needed for a complete installation.
Currently, only Ferrari and Infiniti have vehicles with HID high beams. So for the ultimate lighting on your car you could get H.I.D. low beams and replace the halogen high beams with a set of E-Code high beams.
One final note: many companies are fabricating halogen lights with a blue tint to imitate the look of H.I.D. lights. Many of them even use the name Xenon in their name in an effort to confuse the consumer. You can tell these apart right away because no real H.I.D. system is comprised of just bulbs. You also need ballasts, igniters, and high voltage wiring. Theses imitation bulbs will do little more than reduce night-time visibility. I would strongly discourage you from spending your money on them.