I've run the XAIR OTR from New Zealand in my VZ 6.0L for the last few years ( see pic below ), and AFAIK it has the largest air filter size of any OTR brand in the VT - VZ range (460mm x 180mm ) with a washable / reoilable " Green Filter " from the USA...
https://www.xairperformance.co.nz/otr-cold-air-intake/vt2vxvyvz-v8-commodore.html
Originally they were fiberglass (approx 5mm thick very sturdy ) with a gel coated gloss finish ( same as mine above ) but in recent years they have also made a plastic and carbon fiber version as well.
I very neatly trimmed the OEM radiator shroud around the OTR for the most neat factory look as possible and still retained the MAF.
Their 460mm x 180mm filter is almost double the size of the OEM filter in the factory air box, for maximum Ram Air Effect, their is no comparison.
From all my research, I liked the larger filter design of the XAIR OTR compared to any other brand OTR at the time, hence I bought it and haven't looked back since.
Prior I made my own OCD twin 90mm PVC bell mouthed MCAI modified shroud / factory air box combination, and had great enjoyment making it, and it was very cheap to buy / make at the time and fully sealed.
It worked quite well but after a few years I wanted more...
So I finally bought the XAIR OTR, it was a vast improvement over my prior setup, a lot more throttle responsiveness / pickup, with a fair amount more induction noise as well, so Win Win.
Well worth spending the money on the OTR... IMO...