I've just fitted these pipes to my stead and it appears to run superbly and sound rather nice

My bike has no other tuning modifications, and uses the OEM air filter, but I thought I'd check with V&H about the need for tuneable fule management system and they responded:

Aftermarket motorcycle exhaust will lean your motor out over the stock set up. The ECU does use oxygen sensors to adjust the fuel but it is limited in how much it can adapt to. Depending on your location this adjustability can be further limited by altitude or climate. 
It would be recommended to use a tunable fuel management system but we would not know exactly how lean your bike is without a dyno tune. 

That said, I live in remote WA (Broome) without access to dyno or technical expertise. Is there a simple plug in "tunable fuel management sytem" available - i.e. that would not in itself require tuning?

Thanks,

Well, disappointingly, I didn't get a single response on this forum. However I received a recommendation on the US Sportster Forum.
Based on that I purchased a Power Commander V through Fuel Moto, that was mapped to my Sportster with V&H pipes and free flow air filter.
The bike did appear to be running well before this fitment, but V&H advised me not to run the pipes without using a tuneable injection module - they say it will run too lean.
Fuel Moto supplied the Power Commander V ready to fit, pre-mapped for my bike and its equipment.
The unit arrived and was also fitted today. The bike runs well, but then I thought it was running well prior to fitment. However, I'm told it will improve the longevity so I guess only time will tell.
I'll keep the forum posted if anything of note crops up

Sorry you didn't get any reponse here but your purchase should ensure an appropriate air/fuel mixture. Bare in mind that American tunes provided by places like fuelmoto are based on American fuels, which are a higher grade than our fuel here. So I'd recommend that you use 95 Ron fuel to be safe

Well about five weeks and 1,500km down the track since I fitted the Powever Commander V unit: After installation, the bike accelerates most sweetly and holds speed very smoothly. However, there are pops, farts and crackles on the over-run under high rev engine breaking, so maybe it's running too rich at that time. NB: I did replace the gaskets when putting the V&H pipes on, and cannot detect any leaks.

There do not appear to be any other ramifications, so maybe I just live with it