How much is a 2004 porsche GT2 with mods worth?

my dad is selling his 2004 porsche gt2. we added all rubber f1 tires, changed the axle, put 1 intercooler in each side vent and blow off in the back. also we put a new dual exaust (4 pipes) system. how much do you think it is worth now. we are planning to buy a new GT2. i am not BS-ing. this is a honest question|||First off, Good luck getting A new GT2. You wont get one unless your willing to pay about 300k. I just bout A 2009 911 Turbo Convert. and wanted the GT2 but wasnt ready to wait nor pay the price there asking! As for your 2004, If your dad really has one, People dont want Mod. GT2's. There already done to perfection so your chances of finding A buyer will be VERY hard. Im gonna go with about 120k if your lucky!!!!