If you're in the position to, you can save a load of money by practicing driving outside of your lessons, I assume that's what you're going for?
I spent many hours over weekends with my Dad getting to grips with the clutch and going through the gears, then once I started my lessons practicing all the manoeuvres for my test. I passed first time in less than 7 hours of paid lessons and saved a bunch of cash.
Probably wasn't sensible, but I don't think I had learners insurance, all my practice was done with my Dad driving to a literally deserted industrial estate on weekends, then swapping over and I did some practice.
Don't bother modifying your first car as above, only risk voiding your insurance when you inevitably can't get insured on anything that's modified and you do it anyway and don't declare. My 1.2 16v Clio 2 was plenty quick enough, did tons of motorway driving my first year sat at 80 in it, no need to chase power or try and make it look like something it's not. Can take plenty of speed through corners in it too once you've built up some confidence.