If those numbers are good ones (no leaks), then you are a candidate for a rebuild. The numbers themselves aren't so critical (160 psi is ballpark normal for 98k), but the differences between each cylinder are.
A difference of more than 10% from any cylinder to any other shows some excessive and uneven ring/cylinder/valve guide wear, worse in some cyls than others...this will only get worse from here on out.
You may have many, many miles left, but you are exacerbating the problem every time you drive it hard. Not to mention the fact that you'll be down on power in the 'bad' cylinders.
160 psi times 90% would be 146 psi. This would be a GOOD used motor's range of compression.
160 vs 135...it's just getting a little tired, that's all...HP will gradually slip away.
Hope that made some sense. Someone smarter will come in behind me, don't worry
