There are a lot of people here who have modded well past 100k. I think the big thing is checking over your block carefully. Do compression, cylinder leakdown, and oil pressure tests before you think about modding. Make sure your engine is mechanically up to the challenge. While disassembling, check things over too. Like if you are doing a cam, make sure you look in the cam journals at the bearings. If they look wiped, you can replace them even with the engine in the car with a cam bearing tool. When I did all my stuff on my 3800, these were the steps I took, and it runs awesome and makes great power. Unfortunately, the trans did not fare as well, but that's no fault of mine.
