Best way to get a feel is to see what the market around you is asking for. If you think it is worth more than the surrounding market then you will have to try ebay to reach a larger group.
2016 VW GTI 2.0 Turbo
1989 Sonic Blue LX Coupe, 349 ci, TW heads, TFS Track Heat Intake, 75mm Accufab TB, 80mm ProM, 30 lb. inj, TKO, 3.73, 31 spline w/ TruTrac, MAC 1-5/8" LT headers w/ H pipe, Flowmaster, electric fan Moates QH
391 rwhp & 424 rwtq...Mustang Dyno 11.5@122mph