I have had the Dinan Stage II since it came out earlier this year. It is a great tune for most of us in that it doesn't put undo stress on the engine nor excessive wear on parts. Dinan could certainly put more bang in their tune but it would come with a real cost in terms of higher maintenance.
I don't seem to have any trouble at the track either. Keeping in mind a good driver makes up for allot. If I wanted straight line speed, I wouldn't be driving a BMW. I would be dring my other German car. Oh wait, I do drive my other one.
I have driven both the PPK1, The Dinan Stage II and the JB4 tuned 335i's. All have some great features. It just depends on the driver's comfort, preference and perception.
Now save some money for a real driving school and watch your times really drop!
2011 335i M-Sport Sedan | MHD Custom Tune by Wedge Performance | ER CP | Catless DP | Koni Sport Dampers l Eibach Pro Kit Springs | M3 Suspension Upgrade l BMW Performance Exhaust | BMW Performance Front Grill | OEM Euro M-Sport | 19" Volk Forged Performance ME's | JL Audio HD 900 | Morel Hybrid Components | JL Audio W3v3