Generlly speaking, there will be little difference between performance between the different brands or custom made,
DKNE extractors are designed around the R34 with the aircon pipes taken into consideration, but other than that they will all be suitable.
If you can find a pair of second hand ones at the wreckers or through sau/ebay and they are still in good condition, they arent bent out of shape and are not rusted. then go for it.
I think you might be hard pressed finding any at a wreckers though.