Why should the Tekin be any different to the CC you already have in regard to max amp? And what made you change from the CC, I know the Tekin really should be better as it's sensored but just curious.
As for causing Lipo's to swell, well from my understanding this usually happens when the cells are over discharged or over charged. That's not from trying to draw too much current but when you have run the buggy for long enough that the cells dump and the voltage drops below 3 volts per cell.
The theoretical amount of current a battery can deliver is calculated from the C rating, i.e. your Turnigy cells are 30C and 4500mAh. So that is 4.5A x 30C is 135 amps max current that your cells can supply. A lower C rating will result in less punch. The C ratings can also be optimistic in their rating, and/or reduce over time. I suppose the easiest way I can describe it is driving you old nitro buggy with 15% fuel and then with 30% fuel. In 1/10th I don't think that the batteries are being tested the same way as in 1/8th buggy.
So if your esc and motor can handle more current than your cells can deliver you shouldn't have a problem with Lipo's swelling.
Battery types and brands tends to end up as a heated topic, with many people saying that the cheaper ones are just the same as the more recognised and expensive brands. Until their is a real scientific comparison test then at best all you can do is go by advice from people you trust. There has been tests done by people on YouTube etc that are at best seat of the pants valuation. There has also been some better tests done by bigsquidrc.com, you can find them here
http://www.bigsquidrc.com/lipo-battery-shoot-out/ and here
http://www.bigsquidrc.com/li-po-battery-shootout-2/
But these two comparison 'shoot outs' is filled with US brands some of which we cannot get easily here.
My personal view is that you could of gained more from buying cells that are a bit better, for example these 4S gens ace units from GiantCod
http://www.giantcod.co.uk/gens-5000m...-p-406700.html or two of these 2S batteries linked together
http://www.giantcod.co.uk/gens-5000m...-p-406697.html or if you really want to fly you could try these Intellect 2S packs from Demon Power Products
http://demonpowerproducts.co.uk/prod...hnology-p-5651
As you can see none of these end up being £200 for a 4S set up, but admittedly still more expensive than what you have.
Please don't take my comments the wrong way, but perhaps this should be your area to look at next for improving your set up. And please be aware with my RX8 the default set up for low battery voltage was switched off and to reset this you will need to reprogram this to 4S or 12V. I would strongly recommend that you do this. Also when I connected my RX8 with the hotwire it found an updated firmware/software for it, if you do not have the hotwire and I can get up to Slough at some time that I would be more than happy to update it for you.