I have heard that some snowmobiles have bad calibrations from the factory and an aftermarket clutch kit will help it get better gas mileage and performance, is this true?If so, which company offers the best kit. I have a 2000 ZR 600 EFI. Thanks for the information.

Anyone??? I have a 99 ZR and I wouldn't mind seeing better gas mileage myself? ???

I'm not so sure about gas mileage. Performance is another issue. I have a Black Magic kit in my '98 ZR5 and it's really snappy. I haven't noticed any difference in mileage. I have a custom setup with EPI components in my ZRT that work good. Again, great performance gains but no noticeable difference in mileage.
I've read good things about Goodwin kits also.

I have a 99 ZL 600 EFI, anyone have a good clutch setup recommendation for this sled?

I have a 00ZR6EFI with D&D set up, again I did not notice to much of a gas diff. It sure is snappy though. According to D&D there is suppose to be a savings. If there is it is a small amount.

for a littlle better fuel mileage, try adjustin the e-clip position on your jet needles, bring the clip up one position, that leans the mid range, it 'll all so give you a little more punch in your mid range, this worked real well on my zert600, i have mine at the top position, so it's at full lean on mid range,i picked up maybe 2-4 mpg and have a way better mid range pull, i have a buddie with an xcr 700 who also tried this and he says he picked up 3 more mpg by doin this...hope this helps.

I'm running a D&D kit in my 01zr6, big improvement over stock.

Not so sure on the gas milage. With a better clutch kit you tend to pin it more often.