There are two main types of trains from Shanghai to Wuxi during the day, the semi-highspeed D trains that take about an hour, and the true high-speed G trains that take about 40 minutes.
Both types of trains depart to Wuxi from both the old main Shanghai station, and the new Shanghai Hongqiao near SHA. Don't go to Shanghai South - which only has direct slower train to Wuxi at night.
I am not an expert on Shanghai transport, but Subway Line 2 goes direct from the Maglev station to Hongqiao Station. Shanghai Station is closer, but requires a switch on the subway. Don't know about travel time on taxis to either station.