Aside from the early first generation type kits which are single adjustable DT1's WITHOUT remote canisters, Hotbits essentially offers the DT1, DT2 and the new RSI.
The DT's are similar to the first generation Hotbits, but have a thicker wall and improved pistons and metering system. The RSI are really a rally only set because they require maintenance much more often as is the case with any high-end inverted race/rally set.
As has been stated, the DT2's are really for serious competition use, but they are preferable to RSI's for street duty since they use the same guts, but are lower in cost and much better suited for long term use.
The DT series are available in a few lengths including street (20mm shorter), race (40mm shorter) and rally (20mm longer or so). If required, Larry can also make what he refers to as 'dual spec kits' which have a stock body length strut, but use a longer shock rod to get the stroke.
And before anyone accuses me of being a resident suspension or Hotbits expert, I'm not. I contacted Larry a couple of months back with pretty much the same question as the OP and the above is what I got back from him, just paraphrased to remove irrelevant stuff specific to my setup.