twophat, a couple years ago after Telecom's Bubble fiasco I swore I'd never go with them again. I've been with Orcon which had just turned to crap, so moved back to Telecom after hearing good things about them, and to be honest I couldn't be happier with them, service included.
Paying the difference between the 3GB plan and whatever one you want really is the cheapest way of doing this. Plus unless you're going to be flatting there for a long time do you really want to set up a whole new connection?
If you just upgrade the existing plan, it's prob only going to be about $10-$20 (depending on which plan you want) and you aren't committed. If you find you don't like the service, then you can switch back to the Go plan after 1 month and then look at a second line with a different ISP.
I am constantly impressed when using a friends work paid for telecom connection - the only complaints you really get are the unlimited plan users who are still managing to get 100s of gigs a month and are whining that they want it faster.
If telecom had realistic caps and a naked option I would consider them based on performance.
I can be torrenting at a mates place, getting 1.6 megabytes a second. RDP home, add the same peer to my client and see 16kbyte a sec immediatly afterwards - that 100 times the speed difference. Happens so often its not funny that I will be watching a remaining time download going all over the place when my friend is watching whatever show it is and sending me spoilers on msn... Last one was stargate universe where he gave away that it was sent back in time when I was about 5 mins into it... grrr.....