I've installed their stuff on 350z and g35's when i worked at the shop. We used their parts on a drift car. Megan stuff runs like its parts that cost hundreds more. Top quality, i stand behind them.

And as far as their adds on ebay...

A guy got a megan "knock off" ram horn manifold. All the bends were welded tubes. The megan was straight mandrel bend all the way through with the only welds at the flanges. The knock off cracked like a motherfucker cause of the numerous, shitty welds, and because the metal was thin a shit. The megan ont he other hand...car car broke before it did. We polished that bitch up and it was sold! Just one little story to consider. ebay = $100-150 headers megan = $200 headers...and it lasts....

I love my car...
I love Horsepower...
I love reliability...
So why do i own a DSM again?