Hi all, Well I have'nt visited the site in a while but this is a great site. I ran the MXZ last winter and it ran very well. This is what I had done. Milled head and thicker base gasket, Short intake boots, 501 rotary valve, modified dyno port silencer (call Rich Daily and will fill you in), roller clutch, 1 inch Camo Plast Aggressor track, 168 studs, temp. gauge. My sled ran very well. Beat the 800 Cat every run. I was very happy with my sled. I was planning to buy a new sled for sure this year (probably that 800 MXZ) but my sled ran well last year and its paid for so I will run it again this year.