Looks clean to me, and it has a lot of desirable De Rosa features. I don't know much about the TSX models, but I'd assume it's probably a lot like a De Rosa SLX...the basic difference was more reinforced spirals in the tubing and supposedly stiffer. TSX wasn't around that long because most people liked SLX just fine, it was expensive, and they released MAX and the Nivachrome stuff soon after.

Enjoy it! I'd probably build up with either a modern gruppo or time appropriate 8sp campy ergo stuff...which was an amazing gruppo that saved the company after the debacle that was synchros/c-record. I'd also probably move to a campy headset, though the Ritcheys are very nice.