| 1. Yes because it's all about heat cycles so if you come in after a session you can keep heating the tyre, and I was once told that you're getting heat in the tyre and also into the rim which will hold the heat a lot longer.
2. For the money they're great value for money, but they are not the best I think they use 5 wires to heat the tyres whereas something like HWW have either 7 or 8 wires and a better spread of heat, but they do have great aftercare service, I know a few people who use them and one or two have had issues which they have resolved without any hassle.
3. We've recently found out that a 190 rear does cause issues as the extra width pushes the warmer onto the pipes so some form of guard would be adviseable.
The main benefit for me personally is a mental thing and being able to start cracking on earlier in the session than worrying about warming your tyres which equates to more useful track time over the day | 
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