Hi and welcome to the forums.
I was a total RC tank noob only a few months back..... Well i'm still a noob but a lot more experienced noob thanks to the advice found here... Have a good look round.
Be warned it becomes addictive!! 0 to 5 tanks in three months!! Including a Tamiya Leopard 2A6.
Not sure how much easy upgrades you will find for the HE Leo... You may have been better off spending the extra 50 quid for a Heng Long... That's very upgradable. Some cosmetic upgrade parts may be usable. I have recently upgraded a HE Abrams and still have a long way to go! Got it rewired for Heng Long electrics but the tracks on it are rubber and to change to plastic let alone metal you need to replace the gearboxs/motors/sprockets, rework the road wheels ... change the electrics/control board to Heng Long/Taigen or better. I chose to remove the tank recoil using a Dragon ATRC, split the gun barrel to remove the bullet firing mech in favor of a LED flash, drill out the MG and fit LED flash, change Led headlights, the barrel recoil also needs work ... The list goes on and at a cost!! Hence why I say you may have been better getting the Heng Long or even splashing out for a built Tamiya. But if it's a diy project your after then you have set yourself a fine but not impossible challenge.
Do take heed of Jarndice's advice though. It will save you in the long run.
