I'm new to the forum and am still learning about cars in general. I'm going to sound like a massive newbie here, but whatever.

Just bought a 3.0 Spec B 2006 Automatic and I absolutely love it. It's at 103000kms and hadn't had its 100k service so I got that done with the next one too (all fluids, spark plugs, air filter etc). So 2 major logbook services at Subaru and got a couple of other things fixed up (replaced radiator hoses, pulleys on timing chain). I've noticed after the service the car is a little more sluggish and uses more fuel... I thought at first it was just my imagination but it I can't help but keep thinking it.
Now I've read on the forums here that it could be due to an ECU reset during servicing and eventually the car will go back to normal. Am I on the right track? A "Kido" tune is also recommended from reading on... would this be available in Brisbane? I'd prefer to actually take the car somewhere rather than do it myself due to my lack of experience. Some other questions:
- How do I switch to "sport" mode?
- 98 Octane premium for every fill? Any particular brand?
- Oil? I heard it's wise to top up every month due to excessive oil consumption with these cars. Once again, any particular brand?
- What other maintenance is crucial for running this car? As I said, I've never had a car like this before.
- General mods I can get to increase performance? I'll eventually be looking into aesthetics as well (STI grill is all I can think of right now after tinting and personalized plates)
- The car has a couple of scrapes on the front bumper and a few nicks on the bonnet - Subaru were going to charge me over $500 for a touch up. I'm assuming I can buy my own touch-up paint and do this myself pretty easily, right? Or even have it done somewhere else cheaper?
- The Macintosh head unit is killing me... no AUX port. Are there any easy ways around this? I heard something about using the CD changer input as an AUX?
I really look forward to hearing some feedback from the community here and I appreciate your patience! I know most of my questions have probably been answered already, but I would also like some general advice in what I should be doing first in getting started on my 3.0R journey, so fire away if you have anything useful to provide.

Josh