Ekona

Some engines will also (for whatever reason) prefer different fuels, so what works for one may not work for another. Y'know, just to really complicate matters!

+1 on everything that Chris said

This is NOT a rear diffuser, it's a vortex generator. It goes on the roof of a coupe and not on the rear bumper between the exhaust outlets like a diffuser does.

Lucky you, Magnatec is the single worst oil I can think of to put in any car, much less a performance one. Do yourselves a favour and don't scrimp on your oil, it's not worth it.

The key question is which Z4? The Zed (our one!) will be miles better than a 2.0L, but it'll feel lardy compared with a Z4M

How old is the guy? Tbh after a dangerous driving conviction no sensible insurance company is going to want to touch him in a performance car (and rightly so IMHO) so he's going to have to suck it up and drive something rubbish for a few years. Best place to look for insurers for convicted drivers is in the back of Max Power and the likes. Usually tons of ads in there, I've got no idea if they're any good or not as I'm a wonderful driver with no current convictions on my licence

Generic brake fluid then. Not that that is no good for the car as it's perfectly acceptable, but for the minor extra cost I'd put the RBF600 in as you'll kill that fluid very quickly on track which takes a lot of the point of getting decent brakes away.

Locked as requested by OP.

Which one is it?

Good man While you're there you might as well pop some decent brake fluid in, RBF600 should be suitable for fast road and light track work.

Interesting... but how do new brake lines make such a difference? Goodridge lines (for example) are braided so flex much much less when you press the pedal, giving improved feel and shorter stopping distances.

Write a letter to the guy detailing just how angry you are and what you want to do to him, then burn/bin it. Walk away and be the bigger man, it's not worth getting hauled before the beak over these when you've got a family to think about.

+1, works very well.

What pads? What fluid did you put in there? Brake lines will make a world of difference, really should be everyone's first mod IMHO.

Please don't use Magnatec, it really is the devil's arsehole when it comes to oils. It'll go thin as anything when warm and will do nothing for your engine's protection. Top it up if you must, but then I'd be looking at doing a full change with something decent fairly quickly (sub 1000 miles at least).

I'm telling you that four matched tyres will give a better balanced car than two and two mixed, it really is as simple as that. Will they give more grip? Depends on the tyres, more than likely not, but it will be more stable and that's the key. I'd hope that no-one is daft enough to run tyres that cheap/nasty on their pride and joy, and really the lowest I would be looking to buy would be tyres around the T1R/452 quality. Personally I wouldn't even go that low, but they are at least a known quantity and a quality brand. Tbh if people want to read all this and still run mismatched tyres than they can go right ahead, just please don't expect any sympathy from me when car meets ditch/Armco/tree. If you want to take sensible, logical, reasoned advice from myself that Nissan themselves agree with and ignore it, then that is of course your prerogative.

In all honesty ours was one of (if not the only) stand that bothered to arrange the cars in a way that didn't look like a car park. Show layout really does make the world of difference and no doubt made us stand out from the rest

Absolutely bloody roasting, but a really great day as well. So good to put some names to faces at long last too! Sorry we had to leave so early, but Jo was really starting to suffer with the heat. Few pics, best of a pretty poor bunch sadly as I think I was having something of an off day in photo land I left the one of Chris cleaning the 370 out as it really wasn't a flattering pic at all, although I will now take blackmail requests via PM

If you must then use ionised water at least, not tap crap. Tbh that bottle is only an overflow reservoir, keep an eye on it over the day and just get some coolant from Nissan when you get a chance.

More updates! I've been down to Abbey this morning and they've confirmed what I suspected all along: It's all in my head and I'm a bit of a nutter A thorough test drive proved that there's no issue and I'm just looking for faults now. That said, the uprated clutch line from Adam arrived yesterday (very quick delivery!) so I'm going to fit that as well next week now it's here, if nothing else pedal feel should be improved. Big thanks to the guys at Abbey for this morning, once again 1st class service and it was great to meet you as well.

Change the master cylinder. I've had the same fault recently, and changing the slave did nothing to improve it. However, changing the master solved it perfectly. Also the clutch isn't going to last very long if you rag it like that, so either don't do it or get an uprated clutch. You've more than likely knackered the one already in there by now so it probably needs changing anyway.

What's the actual budget available? Does it have to be fun?

Define 'drive it hard from stationary'? Did they replace the master cylinder as well? How about the clutch line? Why did they rebuild the gearbox?

Morgaldo!

Yes. Yes it does. No, you've changed the entire balance of the car. You've given the rears better grip so you've shifted the bias for both braking and grip backwards, which creates an inherent instability. If your rears have more grip than the front you will experience understeer. You can do that with mixed tyres, tyre pressures or altering the width of the tyres, but the end result is exactly the same. I'm struggling to put it in simpler terms for people to understand, I really don't think it's that hard to comprehend. As far as Docwra and the manufacturers with mixed tyres go, I'm investigating that as we speak. It is true that Pirelli make some tyres that are completely different externally that they claim are safe to work together, and I was unaware of this when writing the original post. I've e-mailed them directly for clarification, and have recieved the most generic response back you can possibly imagine: As such, I intend to push them for details and will post up the results here. All I will say at this point is that at least Pirelli have designed these tyres to work together, despite their apparent mismatch, and so that could explain why they feel happy to recommend this. I have my doubts as to any cars that come with the mixed setup from Pirelli as OEM, however Docwra has first-hand evidence that they do and unless I can prove otherwise I bow to his knowledge on that. That said, as far as I am concerned with my own experiences and research I am still very comfortable saying that putting mismatched tyres onto your car is something only a fool would do.