Just a few observations from owning an Esprit for almost ten years...
Reliability isn't that bad. Let me say it again - it's not that bad. For an exotic, these are remarkably reliable. Try a Mazzer or Lambo, they're a nightmare. Sure, Top Gear loves them, but Top Gear isn't paying to keep them on the road. Jezza bought a Ford GT, after all. No fool, he. With the Esprit, there is the occasional issue that comes from any vehicle when things are packed in tight, and performance is at a premium, but they are not by any means unreliable.
Service isn't simple, but it isn't impossible. In fact, working on my 90 SE, a 4 cyl model, is in a lot of respects easier than my 2001 Mercury Sable wagon. I can pull the fuel pump without removing the tank. I can actually get to the alternator without removing the inside of the fender. Change the plugs in fifteen minutes. Yes, my fan thermostat seems to be out, but just flip on the AC in traffic, temps come back down.
Parts can be expensive, or they can be remarkably inexpensive, if you know what you're looking at. Unlike the other exotics, Lotus doesn't believe in reinventing the wheel. If they can get the mundane components from someone else, so much the better. Some of the Esprit is off the shelf from GM or Toyota, my taillights are from a mid 80's Corolla. Price up a taillight lens for a Boxter... Some of those parts may be from a Euro model, so they can be a bit difficult to obtain, but still cheaper than the equivalent Porsche part.
Most people who have horror stories about Esprits were paying someone else to do all the service. If you're going to own one, it is highly recommended that you have some mechanical skills. You don't need to know how to overhaul an engine or transaxle, but it's a good idea to be able to diagnose minor problems, so you aren't paying someone else $120/hour to learn how to diagnose problems. Quite often, it's just a minor quirk. $500, please.
Example: someone at my office owned a 90 SE like mine. In four years, he put over $10k into service, taking it 80 miles to a non Lotus certified mechanic for everything. In ten years, I've put maybe $3k, and that includes $750 for tires recently. I do all the work myself, including a recent cam belt change and fuel system overhaul.
You're in luck with the 99, it has OBDII diagnostics. Get an OBDII reader, it can reveal an amazing amount of detail. Like having a mechanic standing next to you.
Don't drive it like a fool. Especially on the V8's, the transaxle and clutch are being pushed pretty hard. Respect that, and they'll live. Forget the cheap thrills of a tire smoking start, roll on the power on a long, sweeping ramp, you'll get a far bigger thrill than any drag racing start that could fry the clutch. Gentle power transitions reward this vehicle's handling, anyway.
Oops, gotta go. All this talk reminds me that it's a beautiful day, and there are roads in dire need of exploring... which is the other reason to get one.