While I can understand it is difficult to be told that your money hasn't been well spent and your car isn't quite up to snuff, you really should take their advice. Greg & Seb are experts at enabling you to enjoy the ride in your Z, and they're going to drop truth bombs if that is what is needed to get you there. Most shops would nod and take your money and then shrug when things go wrong. If you just want to enjoy the ride in your Z, listen to what they have to say, make the changes that are within your budget and then see if you can stop smiling when it is all said and done.