Oil Leak, Is my mechanic right? Options

[dmilzoff]

I have a 914-6 with a 3.0. It has been used 1-200 miles per year for the past 4 years and has had moderate oil drips. I accepted the drips in my garage since I only used 1 quart of oil each year. I want to track the car now and I just had major work ($$$) done including changing oil from 50 weight to 10-30 Mobil 1. Now I have more leaks than ever - the car used 2 quarts of oil during 1 day of AutoX. I cannot see any oil leaking. My mechanic says it may be oil leaking past the valve guides into the combusiton chambers - meaning major overhaul and major cost.
Would returning to a higher weight oil (synthetic) help or is the overhaul necessary? Suggestions? Help!!!!

[ChrisReale]

This may be a long shot -- but if you have a front oil cooler, and they refilled the oil without allowing for the extra oil line & cooler volume, that could be at least 2 qts. On my car I had to add approx 2qts once the oil thermostat opened and the front cooler filled up. Just a thought.

I actually considered this, but....if your mechanic knew what he was doing, this would have been taken into consideration. Does the car smoke?