I have the sprint 2 with rear suspension, rack, mudguards and chain guard.
Suspension:
I went to d-tec with the express intention of finding out if I needed none, rear or full suspension. I didn't need front (doesn't seem to make much difference to me), but rear while not vital makes a big difference. It is more difficult to avoid the potholes on a trike, and the suspension allows you the option of putting a front wheel on either side of a hole, and letting the rear suspension absorb the worst of the shock.
Gearing with the stock setup is not a problem. I've never needed the lowest gear, and haven't got a hill round here I can spin out on in the top gear. I may well go for an alfine 11 when the drive train wears out which would result in a slightly narrower range, probably losing a gear at each end - unless I have a double at the front.
Tyres:
I have supremes on my hybrid, and no punctures in 8000 miles. So I put them on the trike. However, as above, options for avoiding problems are more limited with the three tyre tracks, and I've had two in about 800 miles (803.4 to be precise
). One was a thorn, and the other a shard of glass. The tyres are a reasonably easy fit on the rims though, and I can fit them without levers. Definately get a VAR lever for Barakta.
Mudguards:
If you don't have them, Barakta's going to get very wet in the rain. Water sprays off radially from the tyres, and the rider is very close to the wheels. A slight turn of the weels, will give you a facefull, as will a side wind. I also went for the quick release kit so I can take them off easily if the forecast is dry. Although it is not much quicker than using a hex key - just tool free.