You bouth have right.
If I would buy a SAITO, or OS I'll go for 52. But here in Poland ASP are about half cheaper then those two.
I was searching for compare of ASP to OS and SAITO, and didnt find any interestign info.
So I dont really know if ASP 61 FS have the same power like SAITO at this size. Or maybe ASP 61 is closer to SAITO 56 or OS 52.
In technical performance i've found that:
FS52AR, kW/RPM = 0.71/9,500 , Practical RPM = 2,300-9,500 weight = 455 grams
FS61AR, kW/RPM = 0.83/10,500 , PRactical RPM = 2,100-10,400, weight = 445 grams
while OS 52:
Low RPM: 2300, High RPM: 13000, 0.900 bhp @ 12000 RPM, Weight (no muffler): 14.19 oz.
and saito 56:
Low RPM: 2000, High RPM: 12000, Weight (no muffler): 14.46 oz.

So as you can see the ASP 61 is closer to other 52/56 engines in technical data.

Thats why I've decided on 61, but still dont know for shure. Looking fo someone that tells me the other way, because I can still buy ASP 52 , confused