yeah...i feel that way at times..with the dollar where it is any european kit has become THAT much more expensive and the shipping has gone up too because of the valuations and the gas prices.
Overall though the Polini is a FANTASTIC kit that is quite reliable if you don't run it lean and for a 64cc setup will give you more kick than many 70cc setups.
I don't know what the right answer is for the next part but the "well, i already dropped $$$ on this setup, might as well spend more" vs. the "holy crap i spent how much, screw it I'm using what I have" arguments...well, the both hold water.
I guess i am more in the first boat because the whole reason I go for a great setup is for performance and efficiency...and if I can't maximize that or get it to a point that I feel it should be, then I'll usually drop the money or spend the time to get the set up to where I would like it to be.
I think the biggest thing is taht you can't walk into the situation thinking buying a polini makes the bike fast...you need to factor the carb, the pipe, the gearing, etc. everything works in tandem.