Engine Performance problem
1998 Volvo S70 4 cyl Front Wheel Drive Automatic 77000 miles

I have a 1998 Volvo S70 with relatively low miles (77,000). The engine is a bit noisy and rough for a car with so little mileage, and ride noise seems to have increased in the 10,000 miles since I have driven it. Most noticeably, the transmission and engine make a lot of noise as I accelerate (more than usual than with, say, my sister's 1998 Mazda 626 ESV6 with significantly more miles.

I take very good care of my S70 (oil changes every 3,000, new rear brake shoes and pads, regular tune ups and tire balancing).

Would the above problems I have mentioned be at all alleviated by changing the timing belt, water pump and tensioners (sp?) as you suggest. Obviously the timing belt and other components related to it (I assume from your prescription) need to be changed, but could they be the cause of the increased noise level? And also, what is a good price for the all of this work to be done (should I expect the price to be around $700, $800, even $900??)

Thanks