Bad decision?: buying a mystery build
 

So, fellas, talk me out of this. B6 a4 1.8t 5sp q.

Kid tells me it's got an upgraded turbo and clutch and a loud exhaust. Ignoring whether there's any possibility that there's an aftermarket clutch in there, I ask him what turbo, and what software. He says he doesn't know, he didn't get that info from the p.o. who built it... Says he didn't say anything about software

Anyway I get to the car and sure enough it's got a full 2.5" (or somewhere around there) dual exhaust, fmic, 18s, good tires. He says it's got high flow cat which is another big bonus I'm gonna inspect this upon return visit. Starts it up, pretty loud, I would be adding more mufflers I guess. Let's take it for a drive he says, I drive it, 2nd and 3rd gear it rips! Just super torquey and with no lag from like 2 - 4 k And I don't bother taking it much higher than that because I'm already like totally blown away I figured this car was going to run all goofy.

So help me make some assumptions and figure out what exactly to Look for to assess value. (Are the mods worth the price in case the engine and tranny are on their way out is my main question!) I'll assume that its a Chinese k04, which presumably is still capable of kicking you in the pants. So it wasn't like 400hp evo pinned to seat fast but it felt pretty durn fast to me...

What is the cheapest likely software culprit here? Could this fierce torque blast be the result of a chinsy kit? Minimum value? 800 bucks or something?

Now be honest - is there an open source tuning situation for this Audi? How hard is it to tune this mf myself? I'm new on the scene from e36 land where diy tuning is intimidating to say the least but not impossible, and given that I've now stumbled into thrilling 1.8t Quattro land, the e36 project may be getting abandoned entirely...

Where was I...

Oh the oil cap has positive pressure when idling. Is this caused by a vacuum leak? Vacuum pump discharge? Pcv? Sorry I'm not even bothering looking into this right now I'm just hoping you'll make it all clear!

Again I'm trying to assess whether the mods are worth the price of the car in case engine and tranny aren't gonna last very long...

How worn out do these engines get with like 300hp? I'll suggest that's what it felt like it had. Give or take 50

I can replace with early 2000s passat 1.8t engine if blow? because my local junkyard has like 4 of them... Is that 2002 or whatever passat head still better flowing than 2003 a4?

How sturdy is the 5 speed?

So, I realize my laziness with not just looking up answers may be offensive to some. Sry.

Anyway, upon reinspection I'm going to look closely at the turbo, the cats, and possibly at ecu to see if I can't figger what I'd be buying here. The deal is that it's just about the same price as say, a 175k stock a4 without all the mods, and without all the abuse. But I'm thinking it may be substantially cheaper to replace drivetrain than to build a car like this

Oh and if someone could confirm that this would have run like crap and/or thrown codes for lean or overboost or something if it didn't have software support