Is there any material benefit of fitting one apart from the induction sound and the cosmetic improvement?
Some say it does ..some say it don't..
The massive original paper element on these cars is capaple of flowing far more air than the engine will ever need.. providing you change it every ten thousand or so..
In the past 60s 70s some cars came with filters/airboxes that were barely adequate..
This created a market for sporty filters..
take a look at a 70's 150BHP car.. TR6 etc..
I used to fit K&Ns and bellmouths to flowed SU and Webber carbs..
Since the 90s cars have come far better equipped with much better standard filters /airboxes/cold air supply..
(designers had computers)..
flow bench tests seem to indicate that some aftermarket filters flow slightly better when clean but block up more quickly..
also there's the flow/filtration compromise
bottom line is.. if you build an engine that flows more air..camshafts..valves..porting..higher max rpm.. re-map etc.. you may need a larger filter..
or you can fit a posh filter to give the impression that you have a super tuned engine..
horses for courses..