At the time i first wanted a 350Z i was living at home earning around the same as you. I had no bills other then a mobile phone and when i tried to see about a 350Z down the local Nissan (Leicester) i was pretty much laughed at and talked out of buying one. I ended up with an 18 month old 2.0i Z4 then. Less then 2 years later i swapped that for a 2006 350Z GT 300, still living at home not paying rent it was easily affordable. Insurance was actually more on the BMW at just over £1000 for the year.
Things have changed now though and i have a big mortgage so the 350 had to go, i could of kept it but it would of taken up alot of spare income that is better spent on the house. Now that we've settled in and theres a little more money coming in i'll be looking at another possibly although i did say the next car i buy will be a S2 Elise.
Things change and aslong as you buy smart and have a get out plan you should be fine. I owed 12k on my 350Z when i traded it in last april, i got 13k trade in against 6k Tigra. The same car is most likely only worth 9-10k now.
ps. We use to have a C2 VTS aswell, was brand new and got written off by an OAP when she decided to run into the back of us at 50mph when we were stationary. Searh JEJ on c2club.