I can't speak to your car, but I too have an E36 2002 330xi which I plan on upgrading. But I did just upgrade my 528i (97) and it did make a difference. And I was kind of skeptically like you but I was pleasantly surprised by the change. Even from a standing start in the lower rpm's I noticed a peppier response.
Now the bad news. I ended up going to a dealership here locally that is a Dinan dearership as well. So I Dinan'd my car rather than Jim Conforti'd my car. I ordered in the Conforti upgrade for both my 330i and my 528i. In the end, I couldn't install it on either. And we did everything specified, in fact at one point I bought a new battery because we kept getting a 123 code for low voltage. We charged the battery for almost an hour (20 minutes is enough), disconnected the Canadian running lights, took out the fuse for the heated mirrors (not required) and took out all the other recommend fuses. We could not get either Conforti software to install in either car. In fact, we even tried different battery chargers to make sure it wasn't that factor.
So in the end the Conforti is being returned to sender. Also I was smart and didn't try to install it myself; I took it to a local service station that only deals with BMW's. The chap there tried to install it in his car and it wouldn't install. So be warned there are some bad Conforti software sharks out there. I would have preferred to use the Conforti software as you get to keep the shark, but if I lose my software with a Dinan upgrade, I have to pay all over again for another upgrade.