I posted something like this a year ago but Graham gives the real tips. Always double down on the claims. If you never give one inch on the bullshit 90% of the people will believe you and raise you to exalted status. Those other 10%, the ones that know you're full of shit, remember they are the haters. Or even better, they are the liars and don't want you to be so cool and will tear you down with their lies. So never engage them and really don't ever answers any of their questions. They are trying to trap you into slipping up and giving away your tuning secrets. If you play your cards right you can become a legend and no one will ever know. Except all the people that fully know, but remember, never acknowledge them. If you get backed too far into a corner act really angry and maintain the other people are not smart enough to do what you do, or you're on a completely new tuning level. Tell them you know the secrets of Wari Sesu and Big Block Fiero, you eyebrow port your ports and you golfball dent your intakes. Next level shit. Also never show pics of any of your parts, at least not clear pictures. If you are really in a bind steal pics from Netherlander sites, they usually have cool pics and people wont' have often seen them already.
I've watched this technique work for years. I've seen it work for so long that they got out of the scene with spouting bullshit the whole time and people still defend them. Stories build on lies turned into legends on the scene. So if you're going to claim to do 60mph on a stock jawa transistor that you did some porting to remember, never back down.
Also try to judge how many people you are trying to fool. Easy mode is saying you did 50mph on anything. Most people will believe you without raising much suspicion. But you won't get many cool guy points. You might as well say you did 60mph, it's just hard enough that it's impressive, but not unreachable by plenty of other people. You'll get a even mix of belief and skepticism. But fuck da haterz right? 60mph is the best risk reward for bullshit claiming. But if you want to rock big dick style you claim 70mph. It's been done, it's always very impressive, and if you are good and doubling down you can fool enough people to get that cool guy status to just enough people to make it worth it. There will be a lot more people asking you specifics but remember what I already said, keep it vague, no pics, and just tell them they are the stupid people. You can pull this one off if you just hold your line. But don't push anymore than that, if you claim 80mph then no on will believe you and you will get laughed out by everyone. People will demand actual proof and not just "I really did it guise". And frankly your not prepared for that. Remember the best way to lie is to make it just believable enough and holding your line. If you overstep then it all falls down.
Follow these simple steps and you to can starts pwning n00bs on performance forum and be sweet handy's at midwest grom rallies. (please note if you try to pull that big dick claims on the west coast you will get called to actually prove it in person and you really can't afford to do that, because you have built a cardboard house, so keep it in the midwest and jersey where you can pull it off much easier).