100 quid is pushing it[
], metal reinforcement for the chassis and metal gearboxes are a start but you'd be better off sticking with plastic tracks for now and saving for better quality metal ones than buy the really cheap stuff - one of my sets effectively came for free with the tank, and after examining them closely I found there was no knurling on the pins [:@] and so they have already worked loose after little more than 5 or 6 hours running [:@]
(just as well that I need impact late model tracks anyway eh...?
)
Check what kind of axles you have on your chassis before you buy metal swing arms - if you have the later screw in axles, then you can't use the metal arms because the hole in them is too big for the screw. In my experience the screw in axles are less likely to split the suspension arms and don't need replacing (I have 2 Tigers with this style).
If you have the older pin type, you should get the metal arms, as I'll guarranty the chimp who assembled the tank split at least 1 arm when pounding the axles home [:@] - I have 3 Tiger chassis like this, each with an average of 3 cracked arms! 1 had the asiatam hull fitted (which is way out of your budget), 1 had the upgrades you are asking about now, and the other got repaired with the left over arms (and will probably get the asiatam hull in due course).
If you don't mind doing some work to make them fit, Forgebear has some very reasonably priced brass gearboxes that would be better than the HL 'mystery metal' ones. Failing that you could try contacting RCCommand and seeing if you could get hold of some of their steel gears. My only reservations are that the standard ratio boxes makes the Tiger too fast (it runs about the same speed as it would with the stock HL Nylon gears) and the 3:1's are long lead time items at the moment. But they are a direct replacement for the stock HL gearboxes.
I think that should get you up and running. The asiatam hull is nice, but will cost you nearly your entire budget - and the extra weight will probably cause you to struggle on grass with just the standard nylon gearboxes (tho I haven't tried glueing the clutches like some people here recommend)
Anybody else got ideas?