if your looking to build it go with the ls1, 98 is a transition year and if i remember right it has some isssues with the ecm/pcm and tuners but i think it may have gotten worked out, i am seeing that the heads are different and cylinder inserts are thinner as well.

 

IIRC, '98 was a one off year for the ECU. Harder to tune I guess.

I'd say $10k is about the max I'd go regardless of modifications...unless it had 700hp and got 30mpg

 

you could just do an ecu swap to a 99-02 ecu. might have to swap(easier but cost $) or repin the existing wiring harness(much more work) but if you swap both the ecu and harness to 99-02's version, its not that difficult. garydoug helped me repin my 98 for a 2000 engine/trans/ecu with a 99 dash. im no mechanic and i was able to do it in a few days albeit with his very very gracious assistance via these forums.

 

again price all the parts an you will surprised ,that you paid less then you may think ,that rearend was $2000.00 alone or more ,or cost to replace it ,brings you to 6k then say 1k for the rest, the hood was not cheap either ,is 5k ,so look at it that way ,your road an track ready in that car ,where as with a stock one you only road ready ,I am sure of one thing there are people are asking that much for stock one ,an with those upgrades nothing is going to break as easy if you want to get on it ,I guess what some of us were saying about getting one cheaper ,like with me was just cars I had seen on CL ,an sometimes people get better deal couse the person needs to pay there house morage or keep the lights on ,there more apt to sell for a lot less those deals are rare but there out there ,then some just don't known what they have when selling ,I would love to have those upgrades