Yeah, sorry for us to all be downers here, but you'd have to spend a lot of money to get into WS6 territory. Look at the specs for the 2001 model:
Top speed : 165 mph(estimated)
0-60 mph : 5.2 sec.(manual), 6.0 sec.(auto)
0-¼ mile : 13.4 sec @ 106.2 mph(manual)
60-0 braking distance : 120 ft
200 ft skidpad : 0.88 g
That's bone-stock, no mods. Never been a big fan of the styling of that car (screams butt-ugly to me) but you have to got to respect numbers like that (except maybe for the handling numbers). Your best bet with a car like that is to get him onto a very twisty road and beat him by outhandling him on the curvy stuff.
We have a 2002 WS6 and a 2003 SVTF. Hahaha, sorry you'll need a few prayers and "as little money as possible" doesn't fit into this catagory. Maybe www.focus-power.com can help you. I'm a V-8 hata' but this car makes me think twice...
Edit - We once almost ran it with nitrous, we were told it could handle a 150 shot stock. Look out, make sure you know what you're racing. BTW - handling is typical RWD crap so maybe in the twisties you could take it.
Trans-am = Muscle Car
Focus = Economy Car
They are the total opposite. That's like trying to get the Trans-am to get 30+ MPG
You could maybe keep up with a V-6 but not a T/A, keep dreaming. You will need ALOT of $$$
Yeah, I saw a WS6 commercial a few years back, and I will never forget it...
It's nighttime, and a sports car (I think it was a Mustang maybe, but it doesn't really matter) is sitting at a red light. You hear this rumble, and a black WS6 pulls up behind it. The WS6 driver revs his engine... sucks the car up into the Ram Air nostrils and spits its smoldering carcass out the dual exhaust. I was laughing my ass off... it was hilarious. That was one of the best car commercials I have ever seen.
Now every time I see a WS6 behind me, I am like NOOOO, GO AWAY!!!!
Ok, there may be some risk involved, but all you need to do is create some sort of distraction then when the WS6 owner is not looking, remove 2, maybe 3 or 4, of his plug wires. Perhaps he might not notice the rough idle.
I hate to be a downer, but "what he said " applys here, I've driven a ws6 and its prety quick stock, if modded there is no way, however, the plug wire trick would work, all you really need for that one is a really HOT girlfriend willing to go topless for a short period of time
Has the "pro's and con's" of the car plus excerpts from some reviews. There is also a handful of pictures, including that hideous yellow one that I guess was the last of the run. There is a guy in my area who owns one of those and he put a HUGE yellow vinyl "screaming chicken" decal on the back window. I remember the car sitting on the lot at the dealer for a very long time before it finally sold. Speed's great but it's nice to have a car that's not ugly as hell, too. But I guess style is a very subjective matter. 
i wasnt tryin to be cheap....i was seeing wut i would have to do...i will spend the money...im jus finding the cheapest way.....o....and wouldnt alll engine internals without some kind of forced induction have it running low 13's....with out turbo..or supercharged..just internals??