Don't assume the twin won't do a ton. My 790 will easily get there with a bit of wind protection on it. And it will do most things and make them enjoyable, apart from keeping up with litre bikes on a motorway
The twins are a lot of fun once you start working on them.
Of course they won't match the performance of the 675, but it isn't really a fair comparison.
Why not get a cheap carb'd bonnie or thrux & cafe it, as well as a Street3 ?
