I have similar experiences, though I dont think my rx300 seems to shift as "hard" as yours might. Though, I still think my shifting (and acceleration, etc) is rough. I blamed this on the weather. I live in a pretty cold place (winter here is ~5 - 6 mo. and is continually below freezing day and night for ~2 - 3 mo.) and I think the parts, as previously mentioned, just need to warm up. If you need to picture it, think of it as the lubricated oil is near-frozen (well, not really, but it's cold sludge) and makes the car parts harder to move while cold. So warming up the car, the parts and the oil makes for a smoother, more desireable ride :D