I’m doing the conversion on 325i with N53 engine. Local BMW specialist will do it for me ( I’ll be in Canada next two months). When I return to Europe I will have to update the software. When it’s all done I will dyno the car and post the results.
When I bought the car I was deciding between 325i and 330i. The 330 was over $6,000 more than 325. The cars are identical except for the manifold, rear muffler and larger brakes on the 330. Since I was going to replace the muffler and brakes anyway I got the 325 and saved 6K for the mods. I already installed Remus Quad and BMW Performance brakes. Now is the time for upgrading to 330i with better braked and muffler.