The Tiger is a great first build. It should work fine out of the box, yet you can add mods/upgrades as you see fit.
If you cannot find a local hobby store that stocks the Tiger check out the American Armor Foundation (AAF). Not only do they sell Tamiya kits & parts at very reasonable prices, they host one of the nicest indoor battlefields you will every see.
http://shop.aaftankmuseum.com
From the FAQ thread, a little dated but the info should help;
TAMIYA TANK OWNERS FEEDBACK ON TAMIYA TANKS:
NOTE: Updated to reflect reader comments (*)
The purpose of this thread is to give some factual advice to those considering purchasing Tamiya Tanks. I hope to dispel the myth that all Tamiya tanks require hundreds of dollars in upgraded parts just to work. The three tanks listed below that I built were built STOCK, and meant to battle, complete with IR battle systems.
* Except for Gear Reduction and Idler Adjuster in my Tiger I, all the tanks run stock.
We will be listing the following regarding STOCK Tamiya Tanks - no major drive train / track mods.
1) Know Issue(s) - 2) Their Severity - 3) Recommended Fix(es)
If you have built or operate a Tamiya tank, please feel free to add to the list.
ALL TANKS:
1) Turret Rotation Unit is weak - 2) The more you hand turn the turret the worse it gets - 3) Either super glue the clutch or replace with a solid gear (Tamiya Gearbox Kit #72005). Proper cable management can help
* Some like to upgrade from the stock Brass Bearings to Sealed Bearings. Grease MUST be plastic safe. (Jeff)
TIGER I: (built plus feedback)
No Major Issues -
1) The Track Tensioner could be better - 2) Keep an eye on you track through out the day. The tracks can jump on the idler wheel - 3) Fabricate your own Tension system, or purchase an aftermarket tensioner (Daryl Tuners upgrade).
1) Main Gun Barrel Seam - 2) May cause recoil issues - 3) Careful sanding, filling, and painting of the seam,or replace with metal barrel.
* 1) Gear Box Brace - 2) Helps reduce gearbox and chassis flex. Metal Tracks cause more stress - 3) Fabricate your own or purchase after market (pcomm1)
KING TIGER: (have not built, based upon club member feedback)
1) Track Tensioner - 2) This is a major issue. If not adjusted properly, it can lead to track link breakage. - 3) Very careful adjustment of the stock unit, fabricate your own or purchase an aftermarket tensioner (Daryl Tuners upgrade).
1) Track Links are weak - 2) & 3) See Above - Tamiya has sent some tankers replacement tracks.
* 1) Gear Box Brace - 2) Helps reduce gearbox and chassis flex. Metal Tracks cause more stress - 3) Fabricate your own or purchase after market (pcomm1)