DINAN_GT....
You are probably the best person to decide for yourself as you have such extensive mod experience!
But if I were you, I would ask myself:
1) What is my main concern of keeping the current GT? Maintenance costs? Depreciation? Fuel economy?
2) Is there anything that I dislike about the current GT that I simply can't fix and live with?
3) Am I switching cars just so that I can start modding all over from the beginning again?
And those questions, are best answered by yourself..........
