i think i want to go for a lower hp actually because i recon i still need to drive this car. or could i drive it on normal fuel at the hp intended?(safely)

Please provide more info. What were the specific numbers for each cylinder?
Which cylinder has 13% leakage?
:( I'd strongly recommend changing all fluids - each fluid has very specific recommendations - and inspecting everything top to bottom.
I'm sorry I don't quite understand your question. A downpipe will allow you to get to 'bpu' level with the oem twin turbos. This will allow you to run anywhere from oem boost all the way through 26psi. It's the boost controller (not the downpipe) that determines your boost level.
NO intake required for bpu. Like I said, post here with any (potentially bad) advice. The oem cold-air intake provides everything you need for bpu. In other words, you won't pick up any hp from that intake at bpu level.
What you ask here is a VERY complicated question. First of all, I don't know what "normal fuel" is in your city. Can you get 93 octane fuel, as rated using this formula (R+M)/2? Also, is 100 octane fuel available? If you don't have 100 octane fuel available, you can always use methanol injection together with 93 octane fuel, and still produce about 550rwhp or so with reliability.

Overall I agree with the implication of your question: the more you upgrade your car, and the more rwhp you expect from it, the less reliable it will be as a daily driver. I'm aware of bone-stock Mkiv Supras with 250K miles. If you upgrade to 680rwhp, don't expect anywhere near that before you'd need to do some work to it. -BUT- You can easily get to bpu level, and still have an extremely high degree of reliability. At bpu (about 400rwhp), the reliability is still very good (almost as reliable as stock).

Note that if you upgrade to 680rwhp, and you don't run race fuel or methanol injection, its likely to live a very short life. Even a fully race-built motor can be destroyed in a few seconds by detonation.

(i orignally meant 18% leakage total but forgot to correct, sorry) all cylinders were between 143-150 psi and as for the leakage test,
cylinder 1(2%)

cylinder 2(4%)
cylinder 3(3%)
cylinder 4(4%)
cylinder 5(2%)
cylinder 6(3%)

i mean do you think its a good downpipe for a supra TT? after looking at it at the shop i looked it up on the internet and this site says its suitable for a supra TT
http://www.killersupra.com/product.p...6&cat=0&page=1
well here they have all kinds of fuel, even 100 octane fuel, because this country is known for all the fuel it produces thanks to all the crude oil it has, which is good because fuel cost it quite low.

and i was thinking of some engine cooling accesories because out here its REALLY hot, i cant even emphasise how hot it is , what are your thoughts on this?

also the great thing is i can get track experience because my friend works at the losail track in qatar for racing and he can get my car on the track for test drives he said

Do you have specific per-cylinder compression numbers too? Without being there first-hand for the tests, I can tell you that your leakdown numbers look ok. However, your compression numbers look a bit low when compared with your leakdown numbers. For example, a brand-new engine can usually compression test at about 175psi. Compared with that, 143psi seems a bit low. Do you know if the oem procedures were precisely followed for the compression test?

Yes, that looks right.
Good plan. I already mentioned cooling modifications in my post above (last line/link).

well i only have the specifics for leak down on hand because my mate took it for compression test, i was out of the country at this time so ill try and get the specifics when i see him in a few days. ill get the downpipe in a few days aswell so, so far so good, thanks for all the help!

For what it's worth, I'd strongly advise getting the compression numbers re-taken/re-done. Be sure the EFI fuses are removed, ALL of the plugs are removed for the entire test, the throttle plate is open (accelerator pressed to the floor), and you let it turn over about 10 times before taking the reading. Other than that, follow the oem procedures (link above) exactly.

ok, umm ill try and take it for a compression test again this weekend, thx