^ if you are willing to take the time to invest lots of money and attention to detail than it will treat you right. these engines have TONS of potential, look at Shep w/ his talon
http://www.shepracing.com/
You can make AMAZING power with this platform because lots of people have laid down the ground work you just have allot to look out for. The transfer case in these cars is something else i forgot to mention.
Just make sure its in good condition but look forward to taking the engine out and overhauling it completely and changing all your fluids immediatley.
The last 4g63 i worked on was my friends, it snapped the balance shaft belt, so we installed the eliminator kit, replaced the bearings and oil pump, then the head gasket blew. So we changed it. New timing belt, metal HG prepped to perfection and ARP's. New turbo, new ex. manifold the works. Next thing... Timing belt skipped a tooth on hard shift.... i pulled the turbo off and peices of metal started pouring out of the headers... i pulled the head off and i could see through 3 of the pistons. the head.... oh god, valve stems got pushed through the head and up to the cams..... That was the end of that engine.
Its up to you.