Okay, so after a day of work, in which my car is chilling in the sun, I turn my car on and crank up the air conditioner. However the first ~5 minutes is usually hot air being blasted into my eyes. After this time, it cools down.

Is this always how the magnas (TH Exec) perform in the heat (35 has been the hottest so far) or is my unit faulty?

Second, is there a replacement better fan blower? I've noticed mine is fairly weak. Again, this might just be because I'm used to newer, modern cars?

Cheers.

From my experience over the last 2 years with my TL, I'd say your car is normal. I experimented with my red TL last week - the car had been in full sun for 4 hours, air temp was 30C....roof temp was 68C....inside temp was 53C with windows up. I used an Infra-red thermometer which is pretty accurate.
This is one hell of a heat load to get rid of, and again from my experience, you need to drive at least 2Km with all windows down and A/C on full to be in a position where you can wind the windows up and enjoy the aircon.
The only fix or modifier is to use a sunshade on the windscreen or park in the shade.....and have windows down for the first K or so.

Heat soak! The dash and its innards get really hot, the cold air warms up as it blasts through the ducts, once they are cold you will get cold air coming out. Get yourself a sunshade for the windscreen to keep the heat off the dash. Other than that - as above, windows down for a while. You could start your car, turn the air on, lock it with a second key, walk away and come back 5 minutes later . . . . . lol

My KH Xi has the coldest A/C I've ever seen! Mines been drained and re-gassed every year. Costs me $70, but its well worth it. I park my car in the sun all day at work so its like an oven. I just put the climate control on 'AUTO' 21.0 degrees and its blowing cold within 30 seconds. I don't bother opening windows or the sunroof...
Maybe you should get your A/C serviced... Don't get them to just top it up, you'll get better results if they drain and refill, well in my experience, anyway. You can get a new blower at the wreckers if you're that worried about it. Mine was really weak, so I pulled it out and found a bunch of leaves and paper in it. Gave it a good clean so it works as new now!

Yes, well . . . the 134A refrigerant (or whatever number it goes by) in my TS is the original factory fill. lol

I did have a TP regassed with a different gas, and it was BRILLIANT! The bloke used a Hychill product called HR12, a hydrocarbon that works better than 134A, but unfortunately it's flammable in a crash. lol

http://www.hychill.com.au/

Worth a read.

If it ain't broke - don't fix it!

As said above - a car can heat up incredibly quickly and it does take time to cool down. You also do not have a new car so maybe the system is a little bit slower than a brand new car but at the end of the day - the cost to inspect & repair would be quite high and not worth the money. If it works and sometime later the car is cool then why bother worrying about whether it blows fast enough? If you don't want to sit in a hot car then just get a $20 front and side sunshade pack from superdodge auto and wind your windows down before you get into the car.