I swear it makes sense, found and snatched up a good working spotmatic with a nice super tak 55 1.8 for stupid cheap. I keep telling myself it makes perfect sense since I'm wanting a 35mm 3.5and in m42 mount it's less than half the cost of one in k mount. So I'll have a good second body and 2 lenses for under 100 versus 140 for the k mount lens. Now if I could get rid of what I don't use this easy.
Well, if you already have a usable 35 mm SLR, not M42 mount, with lenses then adding another system makes no sense at all. They're all more or less functionally equivalent. GAS it is.
That said, you're spending your money and time, not mine. If building an M42 system pleases you, go to it.
M42 lenses work well on K mount, and if you already have K mount gear, go for it! M42 lenses are fun and simple on aperture-priority modes like the ME Super.
Plus, I totally agree with you on the 35mm f/3.5. My FAVORITE Pentax lens is my SMC Tak 35 3.5. Half the price as a K-mount version. Hell, you could probably snag one of the 35 f/2 Super Taks for the price of the K mount 3.5!
I would not call the need for a 2nd camera GAS. It could however be an early warning sign! Better alertly watch out for further symptoms like looking trough Ebay, Keh and other sites daily or even more than once a day, obsessively thinking about new equipment several times a day and even before you go to sleep, rather buying photo gear instead of things of your daily need ;-)
Proper GAS is always accompanied with unbeatable logic, one that is fluid enough to get you smoothly around any doubt and accommodate all rationalizations you come up with. So, the only question here is "did you get your logic straight?"
I've had severe GAS in the past, and am trying to prevent another attack. My mantra these days is to remind myself that my photographs are considerably worse than what Gene Smith could do with an Ikoflex and a Contax, or HCB with one LTM or M-mount Leica -- so only when what I'm doing is as good as what they could do and my camera gear is limiting my photographic development should I permit myself to buy more gear.
Unfortunately I backslide from time to time, but I'm trying...