1995 Ford Probe mild shake

Recently purchased this 95 ford probe GT with only about 100000 miles as of march 2015. I have been replacing numerous parts that should have been replaced in regular maintenance. Cv axles were replaced at a shop because most of the boots were cracked or ready to, as an example. In short the car has a mild shake in second gear and always at about 2500 to 2800 rpm. Usually the more power is applied the heavier the shake but not always when ambient temperatures are high. Also usually happens going up through the gear but sometimes light shake is felt while descending and on the low end of third gear. A mechanic I go to suggested those axles but I told him they had just been replaced and had not been refurbished although they were Chinese and of an American brand. I suggested engine mounts or possibly transmission mount. This car model has five of them altogether. Am I on the right track or am I barking up the wrong tree?