An Evo runs the streets around here that has shut down many a bigtime competitor in every situation - track, street, from a dig or a roll. His is built from the oilpan up, but he bought it new and showroom stock it could get my LS1, since then it has been turned into a monster, albeit with well into the 5 digits worth of drivetrain now it should be bad. He also has suffered some major breakage, so when built again he always went bigger, badder, stronger if possible. Many street/strip hotrods 'round here, includings several Evos, his is just the baddest I personally know. There was 1 I saw at a local 1/8th mile strip 1 day last winter that ran "no time" but by eye I say he ran deep in the 6s easy, if not tickling high 5s. That thing left the line pure violent!!! When it went, it looked like it bunny hopped forward, huge traction! Those things are fast, but haven't proven long term reliable especially with abuse, and too bad they look the way they do
As for the 'stang( and for that matter the Evo too), it sounds like you ran into some, uhhhh, sandbaggers
As stated, tends to be a norm among the street racing ranks. Just like the Evo, if not more so, mod motor 'stangs can be built to a huge degree. They may be dragging behind 4th gens. stock-to-stock, but with parts and know how most things can be made faster these days. Speaking of, look out for diesel pickups... they are some smokers, literally smokers, showing up at strips and streets around the land. I've been seeing some stock looking 2500s and F250s running around 8 flats, some a bit quicker, at the local 1/8ths. That's 12s in the 1/4 range. Just watch out, turbos and diesel tuning means big power so those 3 ton beasts can run now too, actually quite easily!