DOn't rule out an Auto mate. Go for a drive in a decent one before you make your mind up. They really are good!
As for petrol costs, yeah they drink alot of petrol!
For maintanance side of things, if you can hold a spanner/ratchet and read some good guides on here (along with a little confidence), you'll be fine.
About 3years back, I didn't even touch a car with a spanner. Now after simply reading and fiddling I can easily chance exhausts out, do plugs, coil pack clips, suspension etc, etc.
Heck, I even swapped the engine over in my old Rx7 simply from reading an online guide.
If you can afford the petrol and insurance, go for a TT!