The Strega seems a little odd to me with the vibratory pump for pre-infusion. One of the draws to a lever is that you get a passive pre-infusion with the lever in the down position and if you wanted an active pre-infusion you simply pull down the lever, let it rise until you see the first drop of espresso and then pull the lever down again to start the shot extraction. To me that pump is unnecessary, out of place and missing the point of simplicity (and silence) in lever machines.
My other hesitation is portafilter and basket size of 58mm. The difference in taste and flavor from a 58mm basket to something like a 49mm are huge to me. I know 58mm seems to be 'the norm' in commercial espresso machines, outside of San Marco, but there is definitely something to be said for a small shot from a machine with a 49mm basket! They capture nuanced flavors that 58s just miss.
Now if you took that vibratory pump out of the equation I might be interested in playing with one. With that said, you could find an old single group commercial lever on craigslist for $500, put $500 into refurbishing it and have just as good of a 58mm basket lever machine if not better for $800 less, it would be much more unique and probably better looking too. Sheesh, you could have cannonfodder make a custom wood PF handle, steam / hot water knobs, matching tamper, bean scoop and coffee grinder bean hopper cover and still have money to spare.
Also, what is going on with it having two springs? Is one on top of the other? As long as you do not have an old, decrepit , rusted spring in your machine you should get a ramping pressure profile from it.
