Judder on take up of drive

[shindha]

Hello all, on my 2009 MK3.25 2.0 LF engine MX5,it has covered 38,000 miles, when firing it up especially when cold the revs shoot up to 2000 and then after about 30 seconds start settling down eventually getting to just below 1000 and settling at approximately 750. I have been informed on another forum that this is normal so have no problem with this, if that’s how it is.
When driving, till its up to normal temp it has a little judder requiring a bit of fuel on take up of drive but if I don’t open the throttle enough it tends to drop to nearly 500 revs and judders, but if I open the throttle wider it tends too move off faster. Could it be the drive by wire throttle is lacking in response at the higher pedal setting?
I changed all the fluids, engine, gearbox, diff, oil filter and air filters as well it’s a little better on taking up power a little less judder and only occasionally. I am not sure if it's my driving style as I have been driving diesels for the last 8 years, and that I need to adapt a different approach to taking up power.
The car is a joy to drive, but doesn’t get driven enough.
Thanks for looking and all advice welcome.