there seemed to be several different ones out there when they hit the market
i tried , well had to try they were only 179.00 then from ss autochrome , and I posted on them in one of the first threads . search "ebay headers" lots of input and nonsense on that thread.
those are the atr style repops and being ATR repops you need a downpipe that will workwith atr headers . the design is proven and alot of fast 109s and stage cars run that style header , but even the originals had issues with cracking
the china headers are made nice maybe nicer then the atr originals and welds look great on them but on mine the turbo mtg flange was off . and the crossover gets real close to the flywheel (needs tweaking) and also hits the passenger header tube so some quick work with a BFH is needed there .
the vband as you call them are a cheap attemp to replicate a vband flanges using flat steel rings ( like a large washers) . their flanges are too thin to use a std vband clamp and require a spacer or the gaskets ATR used ,, ideally the flanges they used should be removed and replaced with true v-band flanges and use true v band clamps . they supply a cheap clamp but its not a true vband like was used on genuine ATR headers , you can get vband clamps off ebay .i got the good clamps and used a spacer between their flanges
the gaskets they supply arent that bad but i went with felpro 1400's on the exhasut and used their gasket under the turbo.
as for durability I noticed the weld to their flanges was weak (not much filler used when they tigged them on) and over time was beggining to split at the weld from heat cycliing , i rewelded the backsides of the flanges on the crossover and welded the slip joint and all was good for a while .
i didnt pull the driverside header off and that flange blew off , so now they are off the car and ill do some more repairing and tweak the crossover some more while its out .
as far as performance gains , i really never saw any lower ets and stockers seem to be fine to low 10's just have to weld em up now and then
i would avoid the atr style , the spx-7 headers look like the ones to try as far as being a gauranteed fit but the crossover and the flanges are the same as the atr repops with only difference being the copy of TA headers dual pipe slip over at the connectionby the oil pan , so I would reccomend the same thing , if you go that route replace the flanges .
