how much can my bike take?

The frame is plenty strong enough for this type of riding, provided that you don't go overboard and whack it into a rock or tree. However you will have limited control over the fork, especially bob during climbing and lack of fine tuning for small bumps, and you may find the brakes start to fade out on long downhills. Without a rear can you will need to acquire the skill to keep the rear wheel planted, but plenty of riders still prefer hardtails for all-mountain use and it's generally agreed to be the best type to learn skills on.

Useful ugrades for the future would be fork (so something with compression / rebound adjust and lockout, preferably motion control) but don't fit anything with too much travel or you will upset the geometry, say 100mm as a guide. Increasing the fork travel above what the frame is designed for will affect handling, and often make it worse. If you must go larger choose a U-turn fork so you can increase the travel for downhills and reduce it back down for XC.

Hydraulic disc brakes would also help, with maybe a larger front disc (say 7"). These may not seem overwhelmingly more powerful than your cable discs, but you can achieve much better feel and control of your braking.

The Acera gearing is quite low budget but functional, I would say ride it until it breaks and then upgrade to Deore or LX.

Marv

The Aggressor appears to have been designed for a 100 mm fork. I can't say for sure, but you may find you can't use the full adjustment range of the 85 - 130mm Tora without upsetting the ride / handling.

I would suggest you look at the next one up, the Tora 318 Solo Air 100mm. This is 200g lighter due to having air spring not coil, and is the correct size for your frame (100mm travel). It is listed for XC and AM so should be fine for you.

The exception would be if you contact GT for advice, or if someone comes up with info to suggest that this frame will take the longer travel without problems. It might be OK. I'm just sounding a note of caution.

Having said that, the Tora 318 u-turn is definitely a good 'un.

Marv

Chances of you exceeding the bike's limits without falling off it are very slim.
Knock yourself out, give it large!

The Tora 318 is great i was out riding at 130 yesterday!!!!! Great fork for the cash

If I were you i'd put on a set of tora 318's, the air ones, they are lighter and pretty tough, with poploc, which is nice. Get them at 100mm as the 130mm are apparently a bit flexy. As for strength I currently have a set of the 318 and I'm jumping on them, doing moderate drops as well and they are fine, for the moment, and i weigh 95Kg!!