Bride is one brand you should definitly look into for a couple of reasons
1) the fitment of the base to the car is dead on (I have seen Sparco bases or Recaro bases not fitting due to the holes not lining up, hence extra drilling)
2) compactness, 2 of their models, the FO-type and FG-type are basically "one piece" design that comes with base/slider/sidemount ... the fitment is impectable and they will fit Recaros ...
the FG-type is ultra low, and will fit any of Recaro's 395mm wide seat w/o the need for Recaro sidemount ... for around $175 you get something that fits really well and is super compact ... the slider is kinda funky, but it works ...
the FO-type is slightly higher ... but will fit Recaro's 430mm wide seat (ie the Pole Position or the SPG XL) ... but you have to use the Recaro sidemount instead of the Bride sidemount that comes with the kit, the slider is easier to use .... with this system, the overall seating position will be lowered around 5cm from stock
edit
I checked Bride's website, they dont' make the FG-type for the NSX, only the FO-type ... but for the person that wants to mount his Pole Position, the FO-type should work ...
an alternative you can look into is Chargespeed (
www.chargespeedusa.com), they are a Japanese company too ... the one you would need to buy is the Type-E rail (for sidemount seats such as the Pole Position) which are ultra low, I believe their design is similiar to Bride as well (the base/slider/sidemount comes in one piece)