There are so many different specs - you'd be surprised just how many different bits and bobs people on here have - and of course, we all covert those bits we haven't got!
The AFT - is the electric rising roof - the 'Bongolow' or tintop is a standard van - and there are some sellers making their own roof conversions (see main website)
Do some research on here and the main website, and think about what you'd like to do with your van.
For us, we wanted an all-rounder - to be used as a everyday car (inc. the daily school run - 2 minutes down road!

), 'mums' taxi, camping,day trips and general dogsbody
We weren't sure what type of conversion we wanted, so choose to go unconverted until we'd lived with it for a while and then decide what conversion is best - turns out that unconverted IS best for us!
We choose the split rear seats - great when you need to load big bulky items or just for when a bigger boot is needed
We made a sort of list of wants and needs (with the needs a must, and the wants just added bonus') - our needs were far fewer than our wants!

- for us, our 'needs' were diesel, spilt rears and the AFT - luckily for us, our Jonnie is perfect for us - with everything we'd wrote on our list - save for the armrest and chrome mirror covers that hubby wanted - I bought the armrest off ebay and have convinced hubby that the chrome covers don't match anyway!
But really, the best advice I can give is to just read up on here - there are some cracking people on here, always ready to give advice - and don't be afraid to ask 'silly' questions - god knows, I've certainly asked my fair share!

Venture into the Bongo chat section - it's busier on there - more people to ask (and far more technical than I am!)
Be it Mazda Bongo or Ford Freda (both the same car, just badged differently) - the result will be the same - a HUGE grin that doesn't seem to go away! (ours hasn't anyway and we've had Jonnie for over two years

)