XRAY - Model racing cars

Hi!

A bit of newbie questions here...

I bought an 2WD XRAY XB4 from 2014 in really good shape and for a good price.
I'm used to drive 1:8 4WD and when I tried the XB4 on the track I had issues with jumping, since I was used to correcting the position in the air with the throttle/break. (didnt really think about that it's not possible with a 2WD car when I bought it)

1. What is the correct way to attack a jump with a 2WD car? I couldn't get the nose of the car to not dive when jumping.

2. Is it stupid to start thinking about converting my XB4 to 4WD? What I can see all I need is:

New bottom plate
Driveshafts from diff to wheels
Driveshaft to center Diff/Slipper
Front wheels
Front uprights/bearings etc
Front differential

Anything else?

I have a Muchmore Fleta ZX 8.5T and a Speedpassion Pro 1.1 ESC, would I need to switch engine if converting to 4WD? I guess more torque is needed?

3. Any thoughts about the Muchmore engine and the Speedpassion ESC, is it good electronics? (I've ordered a bluethooth module to the ESC)
If I would like to increase the top speed just a bit (to be more optimized for outdoor track than smaller indoor), should I look at changing the pinion gear (on the engine axle right?) or the spur gear (The big wheel in my slipper right?)

Also trying to understand timings... higher timing on the engine seems to increase how many Amp's it draws from the battery, causing the performance to go up but also the heat.
To find the sweet spot I found some videos on le tube, describing that around 6 Amps is a pretty good starting point. So should I adjust my timing according to that? At the moment its set to 20 Degrees, which seems low compared to all the engine that was configured in the video, they all had a sweetspot at 45-50 degrees.

4. Also got the opportunity to buy two rollers really cheap, one XB4 2WD and one 4WD, both from 2013, it would be totally possible to take my electronics and build one 4WD right? And then I'll have one 2WD without electronics and probably alot of spare parts?
Or is the difference big between 13' and 14'?

Any tips appreciated!

Best Regards Patrik

I bought the rollers, one 2wd and one 4wd from 2013 + loads of spare parts + wheels etc for 100 USD.
I moved all the good parts + electronics from my 2WD, so now I have a 4WD and two 2WD rollers instead

Would love some thoughts on question 1 and 3 though