i just got 18' holeshots and i like them more than the 20' i had on it before them. i also have 14/38 gearing and i love it i still lift the tires every time i shift and the top speed is so much faster. i would not recomend doing this to a stock blaster cause it would loose to much bottom end. remember there are 3 factors affecting top speed and accerlation as far as gearing goes, front sprocket, rear sprocket and tire size.
bigger front sprocket=more top speed,less bottom end
smaller front sprocket=more bottom end,less top speed
bigger rear sprocket=more bottom end,less top speed
smaller rear sprocket=less bottom end,more top speed
smaler tires=faster accerlation, lower top speed
bigger tires=,higher top speed, faster accerlation
ps.- diffrent gearing is used for diffrent things,ex- if you want to drag race your gearing would be diffrent than if you wanted to trail ride. for a stock blaster 14/40 with 18" tires is a good ratio.