Hey guys. New to this Forum, regular on Pelican, E46fan, and a few others. I have an 02 330Ci. I went strictly with the Dinan performance upgrades as I bought my car from a dealer with a CPO and full maintenance. I wanted no hassle in proving my aftermarket modification did not cause the fault (uphill battle that will cost more in time, court/attorney fees (if you go that route) and just plain aggravation.
Dinan offers a warranty that runs parallel to the BMW factory warranty (which is 4 yr 50k miles and if your a CPO, then the CPO kicks in after the factory runs out for another 2 yrs or 100k miles). It does not replace, it just kicks in if their part caused a failure. Think of it as a second warranty. If your BMW dealer is not a BMW dealer, I am sure you will have to go to the Dinan dealer for any failures as the non Dinan BMW dealer will try and say the parts voided your warranty.
If your BMW dealer is also an authorized Dinan dealer, they will get the parts and do the installs for you. I always get a loaner for any Dinan stuff being installed or coordinate it with some service. Can you imagine the dealer that I bought and had install the parts try and claim my Dinan stuff caused any problem! Not. But bottom line is that you end up with upgrades and warranty.
As for all the claims of Dinan being expensive, yes its a bit more expensive, but not in all areas. A Gruppe M intake (which many like for E46's) is about $349 and I think the Dinan is $399. Shark software is about $349 and the Dinan is $399 for Stage 1. If you move up to Stage 2 (have to have the intake) they just charge you $100 more.
I have installed, so I am speaking from experience, Dinan Stage III software, Dinan Cold Air Intake (Carbon Fiber, found a tube for sale), Dinan Engine covers (both of them), Dinan Throttle Body, Dinan Front Strut, Dinan Rear Shock Tower, and the Dinan Automatic Transmission software. There is a big difference in my car compared to it when it was stock. Much more responsive, feels much quicker, stays in gear in manual mode of my steptronic so I control the shifting, higher redline etc.
I recommend the Dinan products, especially with the warranty issue, and they are well tested and work well. They may not push the envelope to the max, but they are a good combination of upgrade and preservation of all that makes your car a BMW.
If my car was not under warranty, I would probably shop around mix and match Dinan and non Dinan products and find some products that were maybe less expensive, but well tested (Gruppe M, Shark, different exhaust, suspension) only because I was not worried about my warranty being voided and I could save some money.
As for resale, I saw a 540 and a Dinan 540 onsale at my BMW Dinan dealer in the used car department. There was a premium for the Dinan and the cars were virtually identical other than for the Dinan products. People will say on the trade in the dealer gives you nothing (yet sells them for more), but that all depends on your negotiation skills and research. You have a car that has more value than your car that is not. Especially if they did all the installs.
Good Luck. :driving