I have both and i guess it just depends on what you really need or want. Don't get me wrong, my L is fast with the mods it has but when you go against a mustang GT or Cobra, you have to factor in the lightnings weight. At least it has some good mods done to it so a GT would have to be highly modded to beat that L or a na Cobra with mods could run with one. My Cobra would put a bus length on my L.
If I drive my L on the hwy, no more than 70mph, i can get around 17-18mpg. When i logged it doing 80mph, i was getting 15mpg. City driving, stop and go and crap...it sucks.
But if i had to choose between a 99 cobra or a 01 L, I would probably get the L. It has power, they still look sick as hell, can tow or still carry a load in the bed. alot of people don't know about the Lightning for some reason, they think F150 until you blow their doors off and you leave them wondering..what the hell did that truck have...
a little of the bad....the 99-01 had the 3-4 thread heads and known for spark plugs to get spit out during driving or going WOT. I would also upgrade the water pump to the 03-04 model which had the better updated impeller and more efficient.
But atleast it's a 01, the 99-00 had some recalls on the intercooler leaking, has a smaller mass air, 20HP less, smaller driveshaft that was steel and could carry less in the back.
What size SC pulley on it? Does it have a lower pulley too? Seems most L guys just go with a lower 4-6lb pulley and leave the top stock but some do drop it to at least a 2.8 on the snout. Mine is stock on the snout and I have a 6lb lower. 391rwhp and 494rwtq and that was on the 5th dyno run. The guy messed up on the 4th run so we didn't know what it put down. it only had a few minute cool down, due to others getting dyno tuned, and he said to had around 7-10rwhp due to it not really getting a cool down. But since the paperwork says 391rwhp, that's what i tell people. I do have a SBTB and a ported plenum sitting around but when i take those off, i'm home porting my SC. Still need to upgrade the rear fuel pumps to 255's and the stock injectors will be fine.
If you do get it, i would still get it on a dyno just to check out the AF ratio.